Automotive air conditioner having condenser and evaporator provided within air duct

ABSTRACT

The evaporator and the condenser are disposed in a duct. First bypass passage is disposed at the side of the condenser and first air mixing damper rotates to control air bypassing amount. Further second bypass passage is formed at the side of the evaporator and second mixing damper rotates to control air bypassing amount. Cooling rate at the evaporator and heating rate at the condenser are varied so that air adjusted in proper temperature is generated and discharged from each outlets into a room. An outside heat exchanger is disposed the outside of the duct. Refrigerant flow is randomly switched among the outside heat exchanger, the evaporator and the condenser so that cooling, heating, dehumidifying, dehumidified-heating and defrosting operations are performed.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part application of U.S. application Ser. No.019,185 filed Feb. 17, 1993 now abandoned, entitled Automotive AirConditioner Having Condenser and Evaporator Provided within Air Duct byIRITANI et al. and is a continuation-in-part of 07/873,430, now U.S.Pat. No. 5,299,431. This application is based upon and claims priorityfrom Japanese Patent Applications No. 3-97290 filed Apr. 26, 1991,3-253947 filed Oct. 1, 1991, 3-319417 filed Dec. 3, 1991, 3-347130 filedDec. 27, 1991, 4-29743 filed Feb. 17, 1992, 4-60616 filed Mar. 17, 1992,and 4-207740 filed Aug. 4, 1992 with the contents of each Japanesedocument and the U.S. application being incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an automotive air conditioner for conditioningair in a room of an automobile. The automotive air conditioner of thepresent invention is effectively applied to an automobile which does nothave a surplus heat source as, for example, an electric automobile.

2. Related Art

Usually, an automotive air conditioner makes use, in order to heat air,of heat from cooling water for an engine for driving an automobile.However, heating of air is performed using a heat pump when the amountof heat of cooling water for an engine is insufficient or when anautomobile does not originally have engine cooling water such as anelectric automobile.

For example, in an automotive air Application No. 60-219114, a flow ofrefrigerant is changed over by means of a four-way valve such that aninside heat exchanger is used either as an evaporator to cool air or asa condenser to heat air.

With the automotive air conditioner wherein cooling operation andheating operation are performed alternatively by changing over of afour-way valve in this manner, since the single heat exchanger changesits function immediately between a function of an evaporator and anotherfunction of a condenser, there is the possibility that, particularlywhen the function is changed over, a large amount of moisture may beblasted from a surface of the inside heat exchanger toward the inside ofthe room of the automobile.

In particular, water condensed on a surface of the inside heat exchangerduring cooling operation is evaporated from the surface of the insideheat exchanger as a result of changing over to heating operation andthen carried into the room of the automobile by a blower. Such blastingof a large amount of water will instantaneously fog a windshield and/orwindow glass. The fog will make an obstacle to a field of view indriving the automobile and is very inconvenient.

Accumulator cycles are conventionally known wherein a subcooling controlvalve is disposed on the downstream side of a refrigerant condenser toobtain a subcooled condition of refrigerant.

An exemplary one of subcooling control valves is disclosed, for example,in Japanese Utility Model Laid-Open Application No. Showa 55-85671 andis shown in FIG. 100. Referring to FIG. 100, the subcooling controlvalve 1100 includes a valve body 1103 for opening or closing a throttlesection 1102 by operation of a diaphragm 1101, a regulating spring 1104for normally biasing the valve body 1103 to open the throttle section1102, and a temperature sensitive tube 1105 for converting a variationof temperature of refrigerant on the downstream side of a refrigerantcondenser (not shown) into a variation of pressure.

The displacement of the valve body 1103 is adjusted by the balancebetween the pressure in the temperature sensitive tube 1105 which actsupon the upper side of the diaphragm 1101 via a capillary tube 1106 andthe high pressure of the refrigerant, and the biasing force of theregulating spring 1104 which both act upon the lower side of thediaphragm 1101, and the opening of the throttle section 1102 dependsupon the displacement of the valve body 1103.

However, in the subcooling control valve 1100 described above, since thebiasing force of the regulating spring 1104 is set in advance so that apredetermined subcooling degree (for example, 5° to 10° C.) may beobtained within the refrigerant condenser, when it is tried to constructsuch a novel subcooling cycle as shown in FIG. 101 or 1017 using thesubcooling control valve 1100, such subjects to be solved as describedbelow are involved.

Referring first to FIG. 101, the subcooling cycle shown constitutes aheat pump cycle for an automotive air conditioner and includes arefrigerant compressor 1200, an interior condenser 1202 disposed in aduct 1201 which introduces blast air into the room of the automobile, asubcooling control valve 1100, an interior evaporator 1203 disposed inthe duct 1201 on the upstream side of the interior condenser 1202, anevaporation pressure regulating valve 1204, an exterior evaporator 1205disposed on the outside of the duct 1201, an accumulator 1206, a bypasspassageway 1207 for bypassing the interior evaporator 1203 and theevaporation pressure regulating valve 1204, and a solenoid valve 1208for opening or closing the bypass passageway 1207.

Now, if the bypass passageway 1207 is closed by the solenoid valve 1208so that the refrigerant flowing out through the subcooling control valve1100 is introduced into the interior evaporator 1203, then airintroduced into the duct 1201 by a fan 1209 is cooled when it passesthrough the interior evaporator 1203, and thereafter, the air is heatedwhen it passes through the interior condenser 1202, and then it blownout into the room of the vehicle. In this instance, when the saturationtemperature of the refrigerant flowing through the interior condenser1202 is 50° C. or around it, as cool air of a temperature close to 0° C.cooled by the interior evaporator 1203 is blown to the interiorcondenser 1202, ideally a subcooling degree of the temperature of 50° C.or so can be obtained at the interior condenser 1202.

On the other hand, if the bypass passageway 1207 is opened by thesolenoid valve 1208 to allow the refrigerant flowing out from thesubcooling control valve 1100 to be introduced into the exteriorevaporator 1205 while an internal air mode is Set So that air in theautomobile room of a temperature of 30° C. or around it is introducedinto the duct 1201, then the air introduced in the duct 1201 is blown tothe interior condenser 1202 while keeping its temperature (30° C.)without being cooled by the interior evaporator 1203. Consequently, onlya subcooling degree of the temperature of 20° C. or so to the utmost canbe obtained at the interior condenser 1202.

In the meantime, the subcooling cycle shown in FIG. 102 constitutes arefrigerating cycle for an automotive air conditioner and includes anexterior evaporator 1210 on the upstream side of an interior condenser1202, and an air mixing damper 1211 for adjusting the amount of draftair to the interior condenser 1202. When the air mixing damper 1211 isopened or closed, cooling air of the temperature of 0° C. or around itcooled by an interior evaporator 1203 is blown to or not blown to theinterior condenser 1202.

For example, when the air mixing damper 1211 fully opens the interiorcondenser 1202 (the position indicated by full lines in FIG. 102) sothat cool air of the temperature of 0° C. or around it is blown to theinterior condenser, if the saturation temperature of the refrigerantflowing through the interior condenser 1202 is 50° C. or around it, asubcooling degree of the temperature ideally of 50° C. or around it canbe obtained.

On the other hand, when the air mixing damper 1211 closes the interiorcondenser 1202 (the position indicated by chain lines in FIG. 102), coolair is not blown to the interior condenser 1202, and the interiorcondenser 1202 acts as a mere refrigerant passageway. Consequently, ifthe external air temperature (the temperature of wind blown to theexterior condenser 1210) is 30° C., then while the saturationtemperature of the refrigerant flowing through the exterior condenser1201 and the interior condenser 1202 is 50° C., only a subcooling degreeof the temperature of 20° C. or so can be obtained even if therefrigerant is cooled ideally to 30° C. of the external air temperature.

Accordingly, where the biasing force of the regulating spring 1104 ofthe subcooling control valve 1100 is set in the subcooling cycles shownin FIGS. 101 and 102 so that the subcooling degree of 20° C. may beobtained at the interior condenser 1202, the subcooling control valve1100 tends to control the subcooling degree of 20° C. even when coolwind of the temperature of 0° C. or around it cooled by the interiorevaporator 1203 is blown to the interior condenser 1202. Consequently, asufficiently high subcooling degree (50° C.) cannot be obtained makinguse of cool wind of the temperature of 0° C. or around it as describedhereinabove.

On the contrary, where the biasing force of the regulating spring 1104of the subcooling control valve 1100 is set so that the subcoolingdegree of 50° C. may be obtained at the interior condenser 1202, evenwhen the temperature of draft air blown to the interior condenser 1202in the refrigerating cycle shown in FIG. 101 is 30° C. or around it oreven when the air mixing damper 1211 in the refrigerating cycle shown inFIG. 102 closes the interior condenser 1202, the subcooling controlvalve 1100 tends to reduce the opening of the throttle section 1102until the subcooling degree of 50° C. is obtained at the interiorcondenser 1202, and consequently, the pressure on the high pressure siderises to a very high level.

In the conventional subcooling control valve 1100, the biasing force ofthe regulating spring 1104 is set so that a predetermined subcoolingdegree may be obtained in the interior condenser 1202 in this manner.Accordingly, the conventional subcooling control valve 1100 cannot copewith the construction of such a cycle wherein the temperature of airblown to the interior condenser 1202 varies over a wide range so thatsubcooling obtained at the interior condenser 1202 varies over a widerange (the subcooling degree cannot be controlled over a wide range),and consequently, the cycle efficiency is low.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an automotive airconditioner for an automobile, which has an engine of the type whereinengine cooling water does not make a sufficient heat source or has nosurplus heat source such as an electric automobile, wherein desirableair conditioning can be performed making full use of a variation of heatinvolved in condensation and evaporation in a refrigerating cycle.

It is another object of the present wherein the capacity of a compressorcan be variably controlled by driving the compressor by means of anelectric motor and air conditioning can be performed efficiently with alow power by suitably controlling the discharging capacity of thecompressor and re-heating of air by means of a heater.

It is a still further object of the present invention to provide anautomotive air conditioner wherein cooling operation or heatingoperation can be performed efficiently by controlling a flow ofrefrigerant to an outside heat exchanger which is provided to complementthe capacities of a heater and an evaporator disposed in a duct.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein cooling operation, dehumidifyingoperation and heating operation can be achieved by suitably controllinga flow of refrigerant discharged from a compressor between an evaporatorand a heater disposed in a duct and an outside heat exchanger disposedoutside the duct.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein cooling operation, dehumidifyingoperation and heating operation can be achieved better by varying theheat exchanging capacities of an outside condenser and an outsideevaporator provided to complement the condensing and evaporatingfunctions of a heater and an evaporator.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the operation thereof can be changedover between heating operation in which refrigerant circulates in theorder of a compressor, a heater, decompressing means and an outside heatexchanger and dehumidifying operation in which the refrigerant flows inthe order of the compressor, the heater, the outside heat exchanger, thedecompressing means and an evaporator by changing over the flow of therefrigerant and heating operation can be maintained while preventingfogging up of the windshield and so forth by changing over the operationsuitably to dehumidifying operation when necessary even in a conditionerof heating operation.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the operation is changed over betweena heating operation condition and a dehumidifying operation condition bychanging over means and defrosting of an outside heat exchanger can beachieved by changing over, even in a heating operation condition, theoperation to a dehumidifying operation condition in a condition whereinit is forecast that the outside heat exchanger may be frosted.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the operation is changed over betweena heating operation condition and a dehumidifying operation condition bychanging over means and defrosting of an evaporator can be achieved wellby changing over, even in dehumidifying operation, the operation toheating operation in a condition wherein it is forecast that theevaporator may be frosted.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the condensing pressure ofrefrigerant in a heater can be varied to control, the temperature of theheater by performing condensing of the refrigerant, in dehumidifyingoperation, by both of the heater and an outside heat exchanger andvarying the condensing capacity of the outside heat exchanger.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the pressure of refrigerant in anevaporator is prevented from dropping below a predetermined valuethereby to prevent fogging up of an inside evaporator by providing aflow of refrigerant which bypasses the inside evaporator and changingover the refrigerant between a flow which flows to the inside evaporatorside and another flow which flows to the bypass passageway by means of asolenoid valve.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein high pressure side refrigerant in arefrigerating cycle can have a sufficient subcooling degree andefficient operation of the refrigerating cycle can be performed bydividing an inside heater into a plurality of inside heaters and usingthe inside heater on the upstream side of a refrigerant flow as acondenser which performs condensing of the refrigerant while using theflow as a subcooler which performs radiation of heat of condensed highpressure liquid refrigerant.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the amount of heat to be absorbedupon operation of a heat pump is increased to enhance the heatingcapacity by using an inside heater as a condenser and using both of aninside evaporator and an outside heat exchanger as evaporators when theheating load is high such as upon starting of heating operation under alow temperature and particularly when heating by inside air circulationis performed.

It is a yet further object of the present invention to provide anautomatic air conditioner wherein an inside heater is divided into aninside condenser and an inside subcooler and throttling amount controlof expanding means can be performed appropriately even in a conditionwherein refrigerant does not substantially flow into either of theinside condenser and the inside subcooler in a cycle in which thethrottling amount of the expanding means is varied so that apredetermined subcooling amount may be obtained with the insidesubcooler.

It is a yet further object of the present invention to provide anautomatic air conditioner wherein a receiver for suitably absorbing avariation of a flow rate of refrigerant which circulates in arefrigerating cycle can be installed well in the refrigerating cycle.

It is an additional object of the present invention to provide anautomatic air conditioner wherein, even in case frost is detected on asurface of an evaporator when dehumidifying operation is to beperformed, defogging of the evaporator can be performed withoutinvolving a great variation of the temperature of air to be blasted.

In order to attain the objects, according to the present invention, theconstruction is employed wherein an evaporator and a heater whichconstitute a refrigerating cycle are disposed in a duct which defines anair passageway.

Further, according to the present invention, a bypass passageway isformed sidewardly of a heater in a duct, and the amount of air to passthe bypass passageway and the amount of air to pass the heater arevariably controlled continuously using an air mixing damper.

Further, according to the present invention, the cooling capacity of anevaporator in a duct and the heating capacity of a heater in the ductare suitably controlled by suitably controlling a flow and a flow rateof refrigerant to flow into the heater and the evaporator in the ductand also into an outside heat exchanger outside the duct.

Further, according to the present invention, a compressor is driven byan electric motor, and the speed of rotation of the electric motor iscontinuously controlled by a controller to variably control thedischarging capacity of a compressor.

Further, according to the present invention, an outside heat exchangeris disposed outside a duct so that the heat exchanging performance of aheater or an evaporator may be complemented by the outside heatexchanger.

Further, according to the present invention, changing over means isdisposed so that a flow of refrigerant passing an outside heat exchangermay be changed over in response to an operation condition required forthe automotive air conditioner, that is, a heating operation conditionor a cooling operation condition. Further, according to the presentinvention, an outside heat exchanger is divided into an outsidecondenser used only for condensation and an outside evaporator used onlyfor evaporation and varying means are provided for varying thecondensing function of the outside condenser and the evaporatingfunction of the outside evaporator.

Further, according to the present invention, changing over means isprovided so as to effect changing over control among a cooling operationcondition wherein refrigerant circulates in the order of a compressor,an outside heat exchanger, decompressing means and an evaporator, aheating operation condition wherein refrigerant circulates in the orderof the compressor, the heater, the decompressing means and the outsideheat exchanger and a dehumidifying operation condition whereinrefrigerant circulates in the order of the compressor, the heater, theoutside heat exchanger, the decompressing means and the evaporator.

Further, according to the present invention, in a condition wherein itis forecast that the windshield of a room of an automobile is fogged,changing over means is controlled to be driven to change over thedehumidifying operation condition.

Further, according to the present invention, in a condition whereinfreezing of an evaporator is forecast, changing over means is controlledto be driven to change over the operation from a dehumidifying operationcondition to a heating operation condition.

Further, according to the present invention, means is provided forchanging over, in a condition wherein freezing of an outside heatexchanger is forecast, refrigerant to be admitted into an outside heatexchanger from a low pressure condition after passing expanding means toa high pressure condition before passing the expanding condition.

Further, according to the present invention, means for varying thecapacity of an outside heat exchanger is provided, and upondehumidifying operation in which both of the outside heat exchanger anda heater perform condensation of refrigerant, the capacity of theoutside heat exchanger is varied to vary the condensing temperature ofthe heater.

Further, according to the present invention, a bypass passageway forflowing refrigerant bypassing an inside evaporator is provided, and aflow of refrigerant is controlled to be changed over by a solenoid valvebetween a flow which flows to the inside evaporator side and anotherflow which flows to the bypass passageway side.

Further, according to the present invention, an inside heater is dividedinto a plurality of inside heaters, and the inside heater on theupstream side in a flow of refrigerant operates as an inside condenserwhile the inside heater on the downstream side in a flow of refrigerantfunctions as an inside subcooler.

Further, according to the present invention, an inner heater functionsas a condenser while an outside heat exchanger functions as anevaporator upon heating operation, and when the heating load isparticularly high, changing over of a flow of refrigerant is controlledso that also the inside evaporator operates as an evaporator togetherwith the outside heat exchanger.

Further, according to the present invention, such a construction isemployed that an inside heater is divided into an inside condenser andan inside throttling amount of an expansion valve is controlled so thata predetermined subcooling degree can be obtained, and refrigerant flowsinto the inside subcooler upon heating operation and upon dehumidifyingoperation.

Further, according to the present invention, such a construction isemployed that a refrigerating cycle wherein a receiver is disposed onthe upstream side of expanding means in a flow of refrigerant is formedand the location of the receiver is always positioned on the upstreamside of the expanding means even if the operation is changed over to anyof cooling operation, heating operation or dehumidifying operation.

Further, according to the present invention, an automotive airconditioner adopts such a construction that, when a frosted condition ofan evaporator is forecast or detected upon dehumidifying operationwherein a heat exchanger on the upstream side in a duct functions as arefrigerant evaporator and another heat exchanger on the downstream sidein the duct functions as a refrigerant condenser, the condition of anoutside heat exchanger is changed over between a condition wherein it isnot used as a heat exchanger between refrigerant and air or it is usedas a refrigerant condenser to another condition wherein it is used as arefrigerant evaporator. Because the construction described above isemployed, with the automotive air conditioner, the evaporator disposedin the duct only performs cooling of air while the heater disposed inthe duct only performs heating of air. Accordingly, such a situation iseliminated that a single heat exchanger alternatively performs coolingof air or heating of air in accordance with an operation condition.Besides, since cooling of air by the evaporator and heating of air bythe heater are used in combination, appropriate temperature control canbe achieved while performing dehumidification of air.

Further, with the automotive air conditioner, the cooling capacity canbe varied to vary the temperature of air after passing the evaporator byvariably controlling the discharging capacity of the compressor.

Further, with the automotive air conditioner, while the outside heatexchanger is disposed outside air and refrigerant, the heat exchangingfunction of the heater or the evaporator by changing over a flow ofrefrigerant to flow to the outside heat exchanger between a flow ofrefrigerant to flow to the heater and a returning flow of refrigerantfrom the evaporator. In this instance, the outside heat exchanger has afunction as a condenser or a function of an evaporator by changing overthe flow of refrigerant. However, since the outside heat exchangerperforms heat exchanging between air outside the duct and refrigerant,even if moisture is produced by a large amount at some location uponchanging over operation, this will not make an obstacle to driving ofthe automobile or the like.

Further, with the automotive air conditioner, since the bypasspassageways are provided sidewardly of the evaporator and the heater andthe ratio of a flow rate of air flowing through either one of the bypasspassageways to another flow rate of air flowing through the evaporatoror the heater is controlled by the damper, cooling of air and heating ofair in the duct can be controlled. As a result, useless cooling anduseless re-heating of air can be eliminated.

Further, with the automotive air conditioner, since the outside heatexchanger is divided into the outside condenser and the outsideevaporator installed separately, also the outside heat exchanger isalways specified in function, and the outside condenser and the outsideevaporator are installed at optimum locations in accordance withrespective functions.

Further, in this instance, since the varying means is employed forvarying the heat exchanging functions of the outside condenser and theoutside evaporator, the functions of the condenser and the evaporatorinstalled in the duct can be variably controlled in connection with thefunctions of the outside condenser and the outside evaporator.

Further, with the automotive air conditioner, since the bypass passagefor flowing refrigerant bypassing the evaporator is provided and a flowof refrigerant is controlled to be changed over between the evaporatorside and the bypass passageway side, when the pressure of refrigerant inthe evaporator becomes lower than a predetermined value, refrigerant canbe flowed to the bypass passageway side. Since refrigerant does not flowthrough the evaporator when refrigerant flows to the bypass passagewayside, the result. Then, when the pressure of refrigerant in theevaporator rises higher than the predetermined value, refrigerant ischanged over so that it may be flowed to the evaporator side again. Thepressure of refrigerant in the evaporator can be controlled to thepredetermined value by performing such changing over as described justabove.

Further, with the automotive air conditioner, since the inside heater isformed separately as a heat exchanger which functions as a condenser andanother heat exchanger which functions as a subcooler for subcoolingcondensed liquid registrant, refrigerant on the high pressure side inthe refrigerating cycle can have a sufficiently high subcooling degree,and efficient operation of the refrigerating cycle can be performed.

Further, with the automotive air conditioner, upon heating operation,radiation of heat is performed by the inside heater while the insideheat exchanger serves as an evaporator in which absorption of heat isperformed, and when the heating load is particularly high such as uponstarting of heating in a low temperature condition, refrigerant passesalso through the evaporator so that absorption of heat may be performedalso in the evaporator. The heating capacity can be enhanced byincreasing the amount of heat absorption in this manner.

Further, with the automotive air conditioner, the inside heater isdivided into the condenser and the subcooler, and a temperature sensingtube is provided for varying the throttling amount of the expandingmeans so that the subcooling degree of refrigerant on the exit side ofthe inside condenser may be substantially constant in order thatrefrigerant passing the subcooler may have a predetermined subcoolingdegree. In the refrigerating cycle having such a construction asdescribed just above, even in a condition wherein no refrigerant flowsinto the inside condenser and the inside subcooler, operation of therefrigerating cycle can be performed with certainty by employing a fixedthrottle in addition to throttling for the expanding means provided bythe temperature sensing tube.

Further, with the automotive air conditioner, since, upon dehumidifyingoperation, the heat exchanger on the upstream side in the duct functionsas a refrigerant evaporator and the heat exchanger on the downstreamside in the duct functions as a refrigerant upstream side, it is cooled,whereupon saturated vapor is removed from the air, whereafter it isheated when it passes through the heater on the downstream side, andafter then, it is blasted into the room of the automobile. Then, if thetemperature of the evaporator drops to a temperature at which frostingoccurs or to a temperature near to such temperature at which frostingoccurs, the controlling apparatus detects or forecasts such frosting bymeans of the frost sensor. Then, the controlling apparatus controls theflow passage changing over means to change over the outside heatexchanger from a condition wherein the outside heat exchanger is notused as a heat exchanger between refrigerant and air or is used as arefrigerant condenser to another condition wherein the outside heatexchanger is used as a refrigerant evaporator.

Then, since the evaporator and the outside heat exchanger both functionas refrigerant evaporators, the evaporating pressure is raised, andfrosting of the heat exchanger on the upstream side is prevented.

It is an object of the present invention to provide a refrigeratingcycle by which an optimal subcooling degree to assure a high cycleefficiency can be obtained even when the subcooling degree obtained isvaried over a wide range by a variation of temperature of refrigerantblown to a refrigerant condenser.

In order to attain the object described above, according to the presentinvention, there is provided a refrigerating cycle, which comprise arefrigerant condenser having a heat exchanging section for condensingrefrigerant passing therethrough into liquid by heat exchange with acooling medium, at least a lower stream area portion of the heatexchanging section being disposed in a temperature field in which thetemperature of the cooling medium varies over a wide range, and asubcooling control valve including a throttle section for throttling arefrigerant flow passageway on the downstream of the refrigerantcondenser, a valve member for opening and closing the throttle section,and a temperature sensitive section for converting a variation oftemperature of the refrigerant on the upstream of the lower stream areaportion into a variation of pressure, the valve member being displacedto adjust the opening of the throttle portion in accordance with thepressure variation of the temperature sensitive section so that thesubcooling degree on the upstream of the lower stream area portion maybe a predetermined value.

Preferably, the refrigerant condenser includes a mounting pipe formounting the temperature sensitive section thereon, and the mountingpipe is provided such that it projects sidewardly of the head exchangingsection on the upstream of the lower stream area portion.

In the refrigerating cycle, the opening of the throttle section of thesubcooling control valve is adjusted so that the subcooling degree onthe upstream in the downstream area of the refrigerant condenser may bethe predetermined value.

Accordingly, the refrigerant flowing into the lower stream area portionof the refrigerant condenser is in the form of liquid refrigerant cooledalready to the subcooling degree of the predetermined value.Consequently, a maximum subcooling degree which can be obtained in thelower stream area portion can be obtained in response to a variation oftemperature of the cooling medium which exchanges heat with therefrigerant in the lower stream area section. In short, even if thetemperature of the cooling medium which exchanges heat with therefrigerant in the lower stream area portion varies over a wide range, asubcooling degree corresponding to a temperature difference between thetemperature of the cooling medium and the saturation temperature of therefrigerant on the upstream of the lower stream area portion(temperature of the cooling medium saturation temperature of therefrigerant) can be obtained.

The above and other objects, features and advantages of the presentinvention will become apparent from the following description and theappended claims, taken in conjunction with the accompanying drawings inwhich like parts or elements are denoted by like reference characters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view showing a preferred embodiment of thepresent invention;

FIG. 2 is a Mollier chart illustrating an operating condition of theautomotive air conditioner shown in FIG. 1;

FIG. 3 is a diagrammatic view showing another preferred embodiment ofthe present invention;

FIG. 4 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 3;

FIG. 5 is a diagrammatic view showing a further preferred embodiment ofthe present invention;

FIG. 6 is a Mollier chart illustrating an operation condition of theautomotive air conditioner shown in FIG. 5;

FIG. 7 is a diagrammatic view showing a still further preferredembodiment of the present invention;

FIG. 8 is a Mollier chart illustrating operation of the automotive airconditioner shown in FIG. 7 in a cooling condition;

FIG. 9 is a Mollier chart illustrating operation of the automotive airconditioner shown in FIG. 7 in a cooling condition;

FIG. 10 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 7;

FIG. 11 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 12 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 11;

FIG. 13 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 14 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 15 is a Mollier chart illustrating an operation condition of theautomotive air conditioner shown in FIG. 14 in cooling operation;

FIG. 16 is a Mollier chart illustrating an operation condition of theautomotive air conditioner shown in FIG. 14 in a heating condition;

FIG. 17 is a diagram illustrating an example of control of theautomotive air conditioner shown in FIG. 14;

FIG. 18 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 19 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 20 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 21 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 22 is a Mollier chart illustrating operation of the automotive airconditioner shown in FIG. 21;

FIG. 23 is a Mollier chart illustrating another operation of theautomotive air conditioner shown in FIG. 21;

FIG. 24 is a Mollier chart illustrating a further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 25 is a Mollier chart illustrating conditioner shown in FIG. 21;

FIG. 26 is a Mollier chart illustrating a yet further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 27 is a Mollier chart illustrating a yet further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 28 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 29 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 30 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 31 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 32 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 33 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 34 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 35 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 36 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 37 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 38 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 39 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 40 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 41 is a flow chart illustrating an example of refrigerating cyclecontrol of the present invention;

FIG. 42 is a flow chart showing another form of the flow chart shown inFIG. 41;

FIG. 43 is a flow chart showing a further form of the flow chart shownin FIG. 41;

FIG. 44 is a flow chart showing a still further form of the flow chartshown in FIG. 41;

FIG. 45 is a flow chart showing a yet further form of the flow chartshown in FIG. 41;

FIG. 46 is a flow chart showing a yet further form of the flow chartshown in FIG. 41;

FIG. 47 is a flow chart showing another example of refrigerating cyclecontrol of the present invention;

FIG. 48 is a flow chart showing a further example of refrigerating cyclecontrol of the present invention;

FIG. 49 is a flow chart showing another form of the flow chart shown inFIG. 48;

FIG. 50 is a diagram illustrating a form of control of a blower for anoutside heat exchanger of a refrigerating cycle of the presentinvention;

FIG. 51 is a flow chart illustrating an example of control when arefrigerating cycle of the present invention is used in dehumidifyingoperation;

FIG. 52 is a front elevational view showing an example of operationpanel used in the present invention;

FIG. 53 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 54 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 53;

FIG. 55 is a flow chart illustrating another example of control of theautomotive air conditioner shown in FIG. 53;

FIG. 56 is a flow chart illustrating a further example of control of theautomotive air conditioner shown in FIG. 53;

FIG. 57 is a flow chart illustrating a still further example of controlof the automotive air conditioner shown in FIG. 53;

FIG. 58 is a flow chart illustrating a yet further example of control ofthe automotive air conditioner shown in FIG. 53;

FIG. 59 is a table illustrating operation modes of the automotive airconditioner shown in FIG. 53 and operating conditions of components ofthe same;

FIG. 60 is a diagrammatic schematic view showing a flow of refrigerantupon heating operation of the automotive air conditioner shown in FIG.53;

FIG. 61 is a diagrammatic schematic view showing a flow of refrigerantupon dehumidifying heating operation of the automotive air conditionershown in FIG. 53;

FIG. 62 is a diagrammatic schematic view showing a flow of refrigerantupon cooling operation of the automotive air conditioner shown in FIG.53;

FIG. 63 is a diagrammatic schematic view showing a flow of refrigerantupon defrosting operation of the automotive air conditioner shown inFIG. 53;

FIG. 64 is a front elevational view showing an example of operationpanel of the automotive air conditioner shown in FIG. 53;

FIG. 65 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 66 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 67 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 68 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 69 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 70 is a diagrammatic schematic view showing a flow of refrigerantupon heating operation of the automotive air conditioner shown in FIG.69;

FIG. 71 is a diagrammatic schematic view showing a flow of refrigerantupon cooling operation of the automotive air conditioner shown in FIG.69;

FIG. 72 is a diagrammatic schematic view showing a flow of refrigerantupon dehumidifying heating operation of the automotive air conditionershown in FIG. 69;

FIG. 73 is a diagrammatic schematic view showing a flow of refrigerantupon dehumidifying defrosting operation of the automotive airconditioner shown in FIG. 69;

FIG. 74 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 75 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 76 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 77 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 78 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 79 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 80 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 81 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 82 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 83 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 84 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 85 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention.

FIG. 86 is a schematic diagrammatic view of an automotive airconditioner in which a refrigerating cycle according to the presentinvention is incorporated;

FIG. 87 is a sectional view of a subcooling control valve;

FIGS. 88 to 91 are Mollier diagrams illustrating operation of therefrigerating cycle;

FIG. 92 is a schematic diagrammatic view of another air conditionershowing a second preferred embodiment of the present invention;

FIG. 93 is a schematic diagrammatic view of a further air conditionershowing a third preferred embodiment of the present invention;

FIG. 94 is a front elevational view of a refrigerant condenser showing afourth preferred embodiment of the present invention;

FIG. 95 is a fragmentary perspective view of part of the refrigerantcondenser shown in FIG. 94;

FIG. 96 is a sectional view of a mounting pipe and a temperaturesensitive tube of the refrigerant condenser shown in FIG. 94;

FIG. 97 is a sectional view of a mounting pipe and a temperaturesensitive tube for comparison with those shown in FIG. 96;

FIG. 98 is a fragmentary perspective view of a modification to a headerof the refrigerant condenser shown in FIG. 94;

FIG. 99 is a front elevational view of a modification to the refrigerantcondenser shown in FIG. 94;

FIG. 100 is a schematic view showing general construction of aconventional subcooling control valve;

FIG. 101 is a schematic diagrammatic view showing general constructionof a conventional air conditioner; and

FIG. 102 is a similar view but showing general construction of anotherconventional air conditioner;

FIG. 103 consists of FIGS. 103A and 103B which together show a flowchart showing control flow of switching operation in air conditionersshown in FIGS. 83-85;

FIG. 104 is an schematic diagram showing operation condition of eachdevice in the first dehumidifying operation and the second dehumidifyingoperation;

FIG. 105 consists of FIGS. 105A and 105B which together show a flowchart showing control flow of switching operation in first dehumidifyingoperation and the second dehumidifying operation;

FIG. 106 is a perspective view of an example showing the presentinvention is applied to an automobile; and

FIG. 107 is a partial perspective view of an example showing loadingposition of an air conditioner of the present invention on anautomobile.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be describedwith reference to the drawings. Referring to FIG. 1, a duct 100 whichdefines an air passageway is disposed in a room of an automobile. A fancase 101 is connected to an end of the duct 100, and a blower 132 isdisposed in the fan case 101. The blower 132 is driven to rotate by amotor 133 disposed at a central location thereof. An inside/outside airchanging over section 130 is connected in the fan case 101, and aninside air inlet port 134 and an outside air inlet port 135 are openedat the inside/outside air changing over section 130. An inside/outsideair changing over damper 131 is disposed in the inside/outside airchanging over section 130, and air to be introduced into the duct 100can be changed over between inside air and outside air of theautomobile.

The duct 100 has a plurality of spit holes formed at an end portionthereof for blowing out conditioned air into the room of the automobile.The spit holes include a vent spit hole 144 for principally blowing outa cool wind toward the head and breast portions of passengers, a footspit hole 145 for principally blowing out a warm wind toward the legs ofblowing out a warm wind toward the windshield. A vent damper 143, a footdamper 143 and a def damper 141 are provided at the spit holes 144, 145and 146 for controlling air flows to the spit holes 144, 145 and 146,respectively.

An evaporator 207 of a refrigerating cycle is disposed in the duct 100,and a condenser 203 of the refrigerating cycle is disposed on thedownstream side of the evaporator 207 similarly in the duct 100. It isto be noted that the evaporator 207 operates as a cooler which takesheat of vaporization away from air for conditioning or air upon heatexchanging thereby to cool the air. Meanwhile, the condenser 203operates as a heater which radiates heat of condensation to air uponheat exchanging thereby to heat the air.

A bypass passageway 150 is disposed sidewardly of the inside condenser203 in the duct 100, and an air mixing damper 154 is disposed forpivotal motion at an end thereof in the duct 100 for variablycontinuously controlling the ratio between the amount of air flowingthrough the bypass passageway 150 and the amount of air flowing throughthe condenser 203. It is to be noted that the refrigerating cycleincludes a compressor 201 which is driven by an electric motor not shownto compress and discharge refrigerant. Since the compressor 201 isdisposed in an enclosed casing integrally with the electric motor, thelocation thereof is not limited to a particular location. It is onlypreferable for the compressor 201 to be disposed at any other locationthan within the room of the automobile for the convenience ofmaintenance and so forth. Refrigerant in a high temperature, highpressure condition discharged from the compressor 201 is condensed by anoutside heat exchanger 202. The outside heat exchanger 202 operates onlyas a condenser and is disposed at a forward location in the advancingdirection of the automobile so that good heat exchanging can be effectedwith outside air. In other words, the outside heat exchanger 202 meetswith a driving wind during driving of the automobile so that refrigerantthereof can be cooled well. Meanwhile, the condenser 203 is coupled tothe outside heat exchanger 202 by way of a refrigerant pipe. Liquidrefrigerant condensed by passage through the condenser 203 flows onceinto a receiver 205. The receiver 205 has a comparatively great volumeso that it can keep surplus refrigerant in the form of liquid thereceiver 205, and only liquid refrigerant is delivered to expandingmeans 206 side. The expanding means 206 is, in the present automotiveair conditioner, a temperature differential expansion valve which variesthe throttling amount thereof in response to a degree of superheat ofrefrigerant on the exit side of the evaporator 207. In particular, theexpansion valve 206 receives a signal from a temperature sensing tube204 and varies the throttling amount thereof in response to the signalso that the superheat on the exit side of the evaporator 207 maynormally be constant. The expansion valve 206 is disposed in theproximity of the evaporator 207. On the other hand, while the locationof the receiver 205 described above is not particularly limited, it ispreferably disposed outside the room of the automobile, for example, inthe engine room for the convenience of maintenance and so forth. Anoperation panel 300 is disposed at a location within the room of theautomobile at which it can be visually observed readily by a passenger.The operation panel 300 includes a fan lever 301 for controlling thespeed of rotation of the blower motor 133, a temperature adjusting lever302 for controlling the opening of the air mixing damper 154, a modechanging over lever 303 for controlling the spit hole dampers 142, 143and 141, an operating lever 304 for controlling the inside/outside airchanging over damper 131 to make a changing over operation, an airconditioner switch 305 for starting operation of the automotive airconditioner, an economy switch 306 for causing the automotive airconditioner to operate in a power saving mode, and an off switch 307 forstopping operation of the automotive air conditioner. A temperaturesensor 322 detects a temperature of air on the exit side of theevaporator 207, and normally the discharging amount of the compressor201 is controlled in accordance with a signal from the temperaturesensor 322 so that the temperature of air on the exit side of theevaporator 207 may range from 3 to 4 degrees. However, when the economyswitch 306 is switched on, the discharging amount of the compressor 201is variably controlled in response to a signal from the sensor 322 sothat the air temperature on the exit side of the evaporator 207 mayrange from 10 to 11 degrees. A sensor 323 detects a pressure of 206. Arefrigerant pressure detected by the sensor 323 is substantially equalto a pressure of refrigerant in the compressor 203, and a saturationcondensation temperature of refrigerant in the condenser 203 iscalculated from the pressure. Subsequently, operation of the automotiveair conditioner having such construction as described above will bedescribed. If the air conditioner switch 305 is switched on and the fanswitch 301 is set to any of positions LO, MID and HI, then thecompressor 201 starts its rotation and the fan motor 133 is rotated at aselected speed. Gas refrigerant in a high temperature, high pressurecondition discharged from the compressor 201 is condensed at partthereof in the outside heat exchanger 202 and condensed at the remainingpart thereof in the condenser 203 disposed in the duct 100. Refrigerantthus condensed into liquid is then separated from gas in the receiver205, and only the liquid refrigerant is supplied to the expanding means206. The liquid refrigerant is adiabatically expanded into mist of a lowtemperature and a low pressure by the expanding means 206 and thensupplied into the evaporator 207. In the evaporator 207, the mistrefrigerant exchanges heat with air supplied thereto from the blower132. In particular, the mist refrigerant takes heat of vaporization awayfrom the air so that it is vaporized while it remains in a low pressurecondition. The thus vaporized gas refrigerant is sucked into thecompressor 201 again. FIG. 2 is a Mollier chart illustrating anoperation condition of the refrigerating cycle. A solid line in FIG. 2shows a condition wherein the air mixing damper 154 assumes its fullyopen position as shown in FIG. 1. In other words, the solid line shows acondition wherein blasting air flows into the condenser 203. As seenfrom FIG. 2, condensation is performed by the outside heat exchanger 202and the condenser 203. In this condition, an enthalpy ΔI obtained in thecondenser 203 is consumed for heating of air, and accordingly, airhaving passed the evaporator 207 and the condenser 203 will perform acooling action by an amount corresponding to an enthalpy Ie. A brokenline in FIG. 2 shows a condition wherein the air mixing damper 154assumes its fully closed condition. In this condition, no flow ofcondensation of refrigerant is performed all by the outside heatexchanger 202. In this instance, however, since the effective capacityof the heat exchangers is decreased by the capacity of the condenser203, the pressure necessary to condense refrigerant is increased. Inparticular, the pressure on the discharging side of the compressor 201is increased a little. On the other hand, the pressure on the suckingside of the compressor 201 is maintained constant independently of theopening of the air mixing damper 154 because it is controlled by theexpanding means 206. Then, in such a condition wherein the air mixingdamper 154 is in a fully closed position as indicated by the broken linein FIG. 2, since the loss in enthalpy by the condenser 203 can beignored, the cooling function of the evaporator 207 can be used as it isfor cooling. Subsequently, a condition of a flow of air in this instancewill be described. Air selectively supplied by the inside/outsidechanging over damper 131 is supplied into the evaporator 207 by theblower 132. Here, when the air passes the evaporator 207, it is cooledby vaporization of refrigerant so that it has a temperature ranging from3 to 4 degrees on the exit side of the evaporator 207, and in thiscondition, it comes to the bypass passageway 150 and the condenser 203.The air flow is suitably selected by the air mixing damper 154. Inparticular, in a condition wherein maximum cooling is required, the airmixing damper 154 closes the condenser 203 so that the cooled air isintroduced as it is to the spit hole side. In case it is desired toraise the temperature of air to be blown out, the air mixing damper 154is opened so that part of the air may be introduced into the condenser203. Air introduced into the condenser 203 is re-heated in the condenser203 to a predetermined temperature and then mixed, in an air mixingchamber 155, with air having passed the bypass passageway 150. The thusconditioned air is blown out into the room of the automobile from aselected one or ones of the dampers 142, 143 and 141. When the modeswitch 303 is at its vent mode position, only the vent damper 142 isopened while the other dampers 143 and 141 remain closed. Consequently,a cooling wind will be blown out principally to the head and breastportions of passengers. On the other hand, when the mode switch 303closed while the vent damper 142 and the foot damper 143 are opened.Consequently, a warm wind having passed the condenser 203 will be blownout principally from the foot spit hole 145 toward the feet ofpassengers while a cooling wind having passed the bypass passageway 150is blown out principally from the vent spit hole 144 toward the head andbreast portions of the passengers. When the mode lever 303 is brought toits foot mode position, only the foot damper 143 is opened while theother dampers 142 and 141 are closed. As a result, air having passed thecondenser 203 is blown out from the foot spit hole 143 toward the feetof passengers. When the mode lever 303 is set to its def mode position,only the def damper 141 is opened while the other dampers 142 and 143are closed. As a result, dehumidified air having passed the condenser203 is blown out from the def spit hole 146 toward the windshield of theautomobile. It is to be noted that, in the automotive air conditionerdescribed above, when the mode lever 303 is set to the foot modeposition, air having passed the condenser 203 will be blown out as it isto the foot portions of passengers. Here, as seen from the Mollier chartof FIG. 2, in the condition described above, the difference in enthalpyat the evaporator 207 is greater by a predetermined amount Ie than thedifference in enthalpy at the condenser 203. However, since aconsiderable part of the cooling capacity of the evaporator 207 isconsumed to condense moisture in the air on a surface of the evaporator207, air having passed the evaporator 207 and the condenser 203 willrise in temperature. In particular, even if the temperature of theoutside air is low, since air cooled when it passes the evaporator 207is re-heated in the condenser 203, the temperature of air when it passesthe condenser 203 is raised to 20 to 25 degrees or so. However, sincethe temperature is comparatively low as a temperature of air to be blownout upon heating, it is desirable, in an operating condition whereinheating is required, to use a PCT heater and some other auxiliary heatsource. While the receiver 205 in the automotive air conditioner of FIG.1 is disposed on the downstream of the condenser 203, it may otherwisebe disposed on the downstream of the outside heat exchanger 202 as shownin FIG. 19. In this instance, condensation of refrigerant heat exchanger203 acts as a subcooler which radiates heat of high temperature, highpressure liquid refrigerant introduced thereinto from the receiver 205.Accordingly, in the present invention, the heat exchanger disposed inthe duct 100 is not necessarily limited to the condenser 203, butincludes a subcooler. Accordingly, in the present invention, acondenser, a subcooler or the like which radiates heat of hightemperature, high pressure refrigerant will be generally referred to asa heater. Further, while, in the automotive air conditioner of FIG. 1,the opening of the air mixing damper 154, the speed of rotation of theblower motor 133 and the speed of rotation of the compressor 201 are setby manual operations of a passenger of the automobile, they mayotherwise be set automatically. FIG. 3 shows such an automaticautomotive air conditioner. Referring to FIG. 3, a sensor 361 detects atemperature of outside air, and another sensor 362 measures atemperature of air in the room of the automobile. A solar radiationsensor 363 measures an amount of the sunlight incident into the room ofthe automobile, and a temperature sensor 364 measures a temperature ofblown out air. Another temperature sensor 365 is disposed on the exitside of the condenser 203 and measures a temperature of air havingpassed the condenser 203. An example of control of the automaticautomotive air conditioner will be described subsequently with referenceto FIG. 4 which illustrates a flow chart of the control. If switching onof the air conditioner switch 305 is detected at step 401, then inputsfrom the various sensors are received at step 402. Then, a necessaryblown out air temperature Tao is calculated in accordance with theinputs at step 403. Then at step 404, it is determined in accordancewith a value of the necessary blown out air temperature Tao whether ornot the operation of the compressor 201 should be in an economy mode. Inparticular, if the necessary blown out air temperature Tao is equal toor higher than a predetermined value, for example, 20 degrees, thetemperature Teo at the exit of the evaporator 207 is set to a highertemperature side preset temperature, for example, to 10 degrees. On theother hand, when the necessary blown out air temperature Tao is lowerthan another predetermined value, for example, 10 degrees, the airtemperature at the exit of the evaporator 207 is set, temperature, forexample, to 3 degrees. Then at step 405, a temperature Te of air at theexit of the evaporator 207 is received from the sensor 322. Thetemperature Te thus received at step 405 and the air temperature Teoobtained at step 404 are compared with each other at step 406. When theactual blown out air temperature Te is higher than the aimed blown outair temperature Teo, this is a condition wherein a higher capacity isrequired for the refrigerating cycle, and consequently, the frequency ofan inverter not shown is raised at step 407 to increase the dischargingcapacity of the compressor 201. On the contrary when the actualtemperature Te is lower than the aimed temperature Teo, this is acondition wherein the capacity of the refrigerating apparatus isexcessively high, and consequently, the frequency of the inverter islowered at step 408 to decrease the discharging capacity of thecompressor 201. Variation of the discharging capacity of the compressor201 is performed when the aimed temperature Teo is lower than the highertemperature side preset temperature, for example, 10 degrees, and theroutine described above is repeated by way of step 409. Then, in case itis judged at step 409 that the aimed temperature Teo is higher than thehigher temperature side preset temperature, the control sequenceadvances to step 410, at which the opening of the air mixing damper 154is controlled. While the opening of the air mixing damper 154 iscontrolled in accordance with the aimed temperature Tao, it isinfluenced further by a temperature of refrigerant in the condenser 203.In particular, when a pressure of refrigerant obtained from the pressuresensor 323 is high, it is judged that also the temperature ofrefrigerant is high, and in this instance, even if the aimed temperatureTao is equal, the opening of the air mixing damper 154 is varied so thatthe air mixing damper 154 may be pivoted by a smaller amount. Inparticular, in the present automotive air conditioner, as control of acooling operation, the discharging capacity of the compressor 201 isfirst varied to achieve power saving operation and then the air mixingdamper 154 is pivoted so that the temperature control may be availableto the high temperature side. Referring now to FIG. 5, there is shown afurther automotive air conditioner according to the present invention,in which the refrigerating cycle is an accumulating refrigerant thereinis installed on the exit side of the evaporator 207 and the sucking sideof the compressor 201, and a capillary tube 211 of a fixed throttle isemployed in place of the expansion valve as the expanding ordecompressing means. In this instance, since the capillary tube 211 doesnot require an excessive installation area, it is disposed in the duct100. FIG. 6 is a Mollier chart of the automotive air conditioner shownin FIG. 5. A solid line in FIG. 6 illustrates a condition wherein theair mixing damper 154 is opened fully so that cooling air is introducedinto the compressor 203. Meanwhile, a broken line in FIG. 6 illustratesanother example wherein the air mixing damper 154 is closed so that thecondenser 203 may not substantially perform a condensing operation. Alsowith the present automotive air conditioner, it can be seen that,similarly as with the automotive air conditioners of the precedingembodiments described above, the pressure on the higher pressure siderises a little when the air mixing damper 154 is closed. Further, sincethe refrigerating cycle is an accumulator cycle, superheat is not takenon the exit side of the evaporator 207. Instead, a predeterminedsubcooling degree is obtained on the exit side of the condenser 203.FIG. 7 shows a still further automotive air conditioner of the presentinvention, in which the outside heat exchanger 202 can be changed oversuch that it is used as a condenser or as an evaporator in accordancewith the necessity. In particular, referring to FIG. 7, a first four-wayvalve 213 and a second four-way valve 214 are disposed at the oppositeend portions of the outside heat exchanger 202. The first four-way valve213 is changed over between a first connecting condition (indicated by asolid line) wherein it interconnects the discharging side of thecompressor 201 and the outside heat exchanger 202 and interconnects thesuction side of the compressor 201 and the refrigerant pipe 220 and asecond connecting condition (indicated by a broken line) wherein itinterconnects the discharging side of the compressor 201 and therefrigerant pipe 220 and interconnects the outside heat exchanger 202and the sucking side of the compressor 201. Also the second four-wayvalve 214 is changed over between a first connecting condition indicatedby a solid line in FIG. 7 and a second 7. In the first connectingcondition, the second four-way valve 214 interconnects the outside heatexchanger 202 and the condenser 203 and interconnects the evaporator 207and the sucking side of the compressor 201. On the other hand, in thesecond connecting condition, the second four-way valve 214 interconnectsthe refrigerant pipe 220 and the condenser 203 and interconnects theevaporator 207 and the outside heat exchanger 202. It is to be notedthat, in the automotive air conditioner shown in FIG. 7, since it has acondition wherein the evaporator 207 and the outside heat exchanger 202are connected directly to each other, an evaporation pressure regulatingvalve 208 is disposed on the downstream of the evaporator 207.Subsequently, an operation condition of the automotive air conditionshown in FIG. 7 will be described with reference to Mollier charts ofFIGS. 8 and 9. FIG. 8 illustrates a condition wherein the first andsecond four-way valves 213 and 214 assume their respective firstconnecting conditions and the outside heat exchanger 202 acts as acondenser. The condition is used principally upon cooling operation insummer. The condition is basically similar to that of the Mollier chartshown in FIG. 6, and the variation in enthalpy at the condenser 203 isadjusted in response to the opening of the air mixing damper 154. FIG. 9illustrates another condition wherein the first and second four-wayvalves 213 and 214 assume the respective second connecting conditions onthe contrary. In the present condition, the outside heat exchanger 202is used as an evaporator, and the present condition is used principallyfor heating operation in winter. In this instance, refrigerantdischarged from the compressor 201 is supplied to the condenser 203byway of the refrigerant pipe 220. Condensation of refrigerant isperformed only by the condenser 203. Accordingly, a great enthalpydifference is obtained at the condenser 203, and consequently, asufficient amount of heat can be radiated. Refrigerant condensed intoliquid by the condenser 203 is decompressed and expanded when it passesthe capillary tube 211 and is supplied in the form of mist into theevaporator 207. Evaporation of refrigerant is performed by theevaporator 207 and the outside heat exchanger 202. It is to be noted,however, that the maintained constant since the evaporation pressureregulating valve 208 is disposed on the downstream of the evaporator207. In particular, it is prevented that the pressure of refrigerant inthe evaporator 207 is lowered excessively so that the temperature at asurface of the evaporator 207 drops to a temperature lower than -2° C.to cause freezing of the surface of the evaporator 207. Particularly inwinter, there is the possibility that, upon admission of outside air,the temperature of the evaporator 207 may be dropped excessively.However, where the evaporating pressure regulating valve 208 is disposedin this manner, otherwise possible freezing of the evaporator 207 can beprevented with certainty. On the contrary, when refrigerant passes theevaporating pressure regulating valve 208, the pressure thereof isfurther dropped such that the evaporating temperature in the outsideheat exchanger 202 becomes lower than the freezing point. Consequently,freezing likely occurs at the outside heat exchanger 202. In order toprevent freezing at the outside heat exchanger 202, high temperaturerefrigerant on the discharging side of the compressor 201 should besupplied to the outside heat exchanger 202 at suitable time intervals.It is to be noted that, in the automotive air conditioner shown in FIG.7, the first and second four-way valves 213 and 214 are controlled bychanging over of the switches 306, 310 and 311. In particular, in acondition wherein the cooler switch 310 or the economy switch 306 is on,the automotive air conditioner performs cooling operation with the firstand second four-way valves 213 and 214 set to the respective firstconnecting conditions. On the other hand, in another condition whereinthe heat switch 311 is on, the first and second four-way valves 213 and214 assume the respective second connecting conditions, and theautomotive air conditioner performs heating operation. It is to be notedthat it is also possible to modify the automotive air conditioner shownin FIG. 7 into an automatic automotive air conditioner employing amicrocomputer. In this instance, sensors similar to those shown in FIG.3 may be employed, and the discharging capacity of the compressor 201,the opening of the air mixing damper 154 and changing over operations ofthe first and second four-way valves 213 and 214 are controlled by wayof the controller 300. Such control will be described with reference toFIG. 10, calculated at step 403 in accordance with inputs received atstep 402 from the various sensors, it is judged at step 411 inaccordance with the aimed blown out air temperature Tao whether coolingoperation or heating operation should be performed. In case a coolermode is determined, the first and second four-way valves 213 and 214 arechanged over to the respective first connecting conditions indicated bysolid lines in FIG. 10 at step 412. In the cooler mode, control of ablown out air temperature is executed using steps 405, 406, 407, 408,409 and 410 similar to those of the cycle shown in FIG. 4. In case aheater mode is determined at step 411, the first and second four-waryvalves 213 and 214 are changed over to the respective second connectingpositions indicated by broken lines in FIG. 10 at step 413. In theheater mode, the air mixing damper 154 is basically held in a fully opencondition, and to this end, an instruction is delivered at step 414 tofully open the air mixing damper 154. At step 415 after then, a pressureof refrigerant is inputted from the sensor 233 and a condensingtemperature at the condenser 203 is calculated in accordance with therefrigerant pressure. Then, a condensing temperature Tc obtained fromthe sensor 365 is compared at step 416 with the aimed temperature Taocalculated at step 403. In case the condensing temperature Tao ishigher, the control sequence advances to step 417, at which thefrequency of the invertor is lowered to decrease the dischargingcapacity of the compressor 201. On the contrary in case the condensingtemperature Tc is lower, the frequency of the invertor is raised at step418 to increase the discharging capacity of the compressor 201. In thismanner, in the operation illustrated in FIG. 10 of the automotive airconditioner, power saving operation of the compressor 201 by control ofthe invertor takes precedence in either of the cooler mode and theheater mode.

FIG. 11 shows a yet further automotive air conditioner according to thepresent invention. While the evaporator 207 in all of the automotive airconditioners described above is disposed such that it occupies theentire air passing position in the duct 100, it is disposed, in thepresent automotive air conditioner, such that a bypass passageway 160may be formed sidewardly of the evaporator 207 in the duct 100. Further,a bypass damper 159 is disposed for pivotal motion in the duct 100 sothat the rate between an amount of air flowing in the bypass passageway160 and another amount of air flowing in the evaporator 207 may becontrolled by means of the bypass damper 159. Construction of the otherportion of the automotive air conditioner is similar to that of theautomotive air conditioner described hereinabove with reference to FIG.7.

Accordingly, in the automotive air conditioner shown in FIG. 11, theflow rate of air to flow into the evaporator 207 principally uponheating operation can be decreased by means of the damper 159. Since theblown out air temperature of the evaporator 207 is that for cooling ofair even upon heating, if the flow rate of air to pass the evaporator207 is decreased by means of the damper 159 in this manner, then theheating capacity is enhanced as much.

Subsequently, an example of control of the controller 300 in theautomotive air conditioner shown in FIG. 11 will be described. Thepresent control is characterized particularly in control of the openingof the damper 159. In the flow chart of FIG. 12, control of the damper159 is executed when a heater mode is determined at step 411. In otherwords, in case a cooler mode is determined at step 411, the damper 159closes the bypass passageway 160 so that the entire amount of air fromthe blower 132 may pass the evaporator 207.

When a heater mode is determined at step 411, a necessary dehumidifyingamount is calculated at step 419. The necessary dehumidifying amount iscalculated depending upon whether or not the inside/outside air changingover damper 131 is in an inside air admitting condition and inaccordance with an amount of a wind of the blower 132, a relativehumidity in the room of the automobile and so forth. Then, at step 420,the damper 159 is continuously controlled in accordance with thenecessary dehumidifying amount. In particular, when the necessarydehumidifying amount is great, air is introduced into the evaporator 207to increase the dehumidifying amount of the evaporator 207. Then, afterpivoting control of the damper 159 is executed at step 420, thedischarging capacity of the compressor 201 is varied by varying thefrequency of the invertor similarly as in the control describedhereinabove with reference to FIG. 4, thereby controlling the blown outair temperature. Also in this instance, the air mixing damper 154 is inthe fully open condition so that the entire amount of air is flowed intothe condenser 203.

Accordingly, with the automotive air conditioner shown in FIG. 11,cooling operation and heating operation can be performed well, andparticularly upon heating operation, the heating efficiency can beenhanced by restricting the function of the evaporator 207 to a minimumlimit necessary for dehumidification.

An automotive air conditioner according to a yet further embodiment ofthe present invention will be described subsequently with reference toFIG. 13. The present automotive air conditioner includes fourth checkvalves 216, 217, 218 and 219 in place of the second four-way valve 214described hereinabove.

In the following, description will be given of functions of the checkvalves. When the first four-way valve 213 is at the first connectingposition indicated by a solid line in FIG. 13, high pressure refrigerantdischarged from the compressor 201 comes to the check valves 216 and 218by way of the outside heat exchanger 202. Then, due to a function of thecheck valve 218, the refrigerant will not flow to the evaporationpressure regulating valve 208 side but will all flow to the condenser203 side past the check valve 216. After then, the refrigerant isdecompressed by the decompressing or expanding means 211 and introducedto the evaporation pressure regulating valve 208 and the check valve 219by way of the evaporator 207. The check valve 218 on the downstream ofthe evaporation pressure regulating valve 208 can mechanically flowrefrigerant therethrough toward the downstream of the evaporationpressure regulating valve 208. However, since the downstream of thecheck valve 218 is in a high pressure condition on the discharging sideof the compressor 201 as described hereinabove, the low pressurerefrigerant cannot pass the check valve 218. On the other hand, sincethe check valve 219 is communicated with the low pressure side of thecompressor 201 by way of the accumulator 212, refrigerant can pass thecheck valve 219 readily. Accordingly, refrigerant will all be returnedto the compressor 201 past the check valve 219.

Subsequently, a flow of refrigerant when the first four-way valve 213 isin the second connecting position indicated by a broken line in FIG. 13will be described. In this instance, refrigerant in a high pressurecondition discharged from the compressor 201 comes to the check valves219 and 217. Then, the flow of refrigerant is stopped by the check valve219, and consequently, all of the refrigerant flows to the check valve217 side. Then, the flow of the refrigerant having passed the checkvalve 217 is stopped by the check valve 216, and consequently, all ofthe refrigerant flows to the condenser 203 side.

The refrigerant having flowed through the condenser 203 is then put intoa low pressure condition when it passes the decompressing means 211 andthen flows to the evaporation pressure regulating valve 208 side by wayof the evaporator 207. Thus, since the check valve 219 is acted upon atan end thereof by a high pressure on the discharging side of thecompressor 201, refrigerant after having passed the evaporator 207cannot pass the check valve 219. Accordingly, all of the refrigerantpasses the check valve 218 past the evaporation pressure regulatingvalve 208. The refrigerant having passed the check valve 218 will allflow into the outside heat exchanger 202. This is because the exit sideof the check valve 216 is at a high pressure on the discharging side ofthe compressor 201 and the refrigerant cannot pass check valve 216. Therefrigerant having passed the outside heat exchanger 202 will thereafterreturn to the suction side of the compressor 201 by way of the firstfour-way valve 213.

In this manner, with the automotive air conditioner shown in FIG. 13,the functions of the second four-way valve 213 are substituted by thefour check valves 216, 217, 218 and 219. Accordingly, electric movableelements can be reduced, and consequently, the automotive airconditioner has an improved durability.

Subsequently, a yet further automotive air conditioner of the presentinvention will be described with reference to FIG. 14.

In the automotive air conditioners of the foregoing embodimentsdescribed hereinabove, only one outside heat exchanger, that is, theheat exchanger 202, is employed and is either used as a condenser(embodiments shown in FIGS. 1, 3 and 5) or is changed over between afunction of a condenser and another function of an evaporator(embodiments shown in FIGS. 7, 11 and 13). However, in the automotiveair conditioner of the embodiment shown in FIG. 14, two outside heatexchangers are provided including an outside condenser 202 and anoutside evaporator 210. Besides, in the automatic sir conditioner of thepresent embodiment, a condensing damper 253 is provided as condensingside varying means so that the flow rate of air to flow into the outsidecondenser 202 may be varied. Similarly, an evaporating side damper 254is provided as evaporating side varying means so that the flow rate ofair to be sucked into the outside evaporator 210 may be variablycontrolled.

In this manner, in the automotive air conditioner of the embodimentshown in FIG. 14, the two outside heat exchangers are always usedindividually as a condenser (outside condenser 202) and an evaporator(outside evaporator 210). Here, the outside condenser 202 is usedprincipally upon cooling operation to cool refrigerant into liquid.Accordingly, preferably the outside condenser 202 is installed, forexample, at a front portion of the automobile so that it may meet with adriving wind of the automobile. In the meantime, the outside evaporator210 is used to evaporate refrigerant principally upon heating.Preferably, the outside evaporator 210 is disposed such that, forevaporation of refrigerant upon heating, it may not meet with a drivingwind of the automobile or the like when the temperature of outside airis low. More particularly, preferably the outside evaporator 210exchanges heat with ventilation air from within the room of theautomobile. Therefore, the outside evaporator 210 is disposedintermediately of a flow of ventilation air at a rear location of theroom of the automobile.

In this manner, with the automotive air conditioner shown in FIG. 14,the outside condenser 202 and the outside evaporator 210 can both bedisposed at respective optimum locations.

Further, since the dampers 253 and 254 are employed in the presentautomotive air conditioner, the heat exchanging capacities of theoutside heat exchangers 202 and 210 for which no function is requiredfor construction of a refrigerating cycle can be minimized. For example,it is demanded, upon cooling operation, that refrigerant be evaporatedonly at the evaporator 207, add in this instance, the evaporator damper254 closes the outside evaporators 214 and 210 so that a flow of air maynot flow into the outside evaporator 210. On the other hand, uponheating operation, it is desirable that condensation of refrigerant beperformed in the condenser 203 disposed in the duct 100, and in thisinstance, the condensing damper 253 closes the outside condenser 202.

Those conditions will be described with reference to the Mollier chartsof FIGS. 15 and 16. FIG. 15 illustrates a cooling condition, in whichrefrigerant compressed to a high pressure by the compressor 201 is firstcondensed by the outside condenser 202 and then condensed by thecondenser 203 disposed in the duct 100. Further, in this condition, theoutside evaporator 210 is substantially prevented from performing heatexchanging by the evaporation damper 254, and consequently, evaporationof refrigerant is performed only by the inside evaporator 207.

On the other hand, FIG. 16 shows a heating condition. In this condition,the condensing damper 253 closes the outside condenser 202, andconsequently, condensation of refrigerant is performed only by theinside condenser 203. The evaporating pressure of the evaporator 207 isregulated by the evaporation pressure regulating valve 208, andevaporation of refrigerant which has been further decompressed uponpassing through the evaporation pressure regulating valve 208 isperformed by the outside evaporator 210.

In the automotive air conditioner shown in FIG. 14, in addition to thedischarging capacity of the compressor 210, the opening of the airmixing damper 154 and the opening of the bypass damper 159, also theopenings of the condensing side damper 253 and the evaporating sidedamper 254 are controlled by controller 300. The openings and thecapacity are controlled principally in accordance with an aimed blownout air temperature Tao calculated in accordance with values inputtedfrom the various sensors. A concept of the control is illustrated inFIG. 17. The axis of abscissa of FIG. 17 indicates the aimed blown outair temperature Tao, which increases in the rightward direction in FIG.17. In particular, a heating condition is shown at a right-hand sideportion while a cooling condition is shown at a left-hand side portionof FIG. 17.

The location A in FIG. 17 shows a maximum cooling condition, in whichthe capacity of the compressor 210 presents its maximum and the amountpivotal motion of the air mixing damper 154 is 0, that is, no air isblown to the condenser 203. Meanwhile, the amount of pivotal motion ofthe bypass damper 159 is at its 100%, and consequently the entire amountof air passes the evaporator 207. Further, the condensing side varyingmeans 253 is open to allow air to be admitted into the outside condenser202. In the meantime, the damper 254 on the evaporating side varyingmeans is closed so that no air is admitted into the outside evaporator210. When the cooling capacity required for the automotive airconditioner decreases (point B in FIG. 17) as the cooling load decreasesafter then, the capacity of the compressor 201 is decreased first. Inparticular, the speed of rotation of the compressor driving motor islowered to decrease the cooling capacity so that the temperature of airon the exit side of the evaporator 207 is raised. Consequently, powersaving operation is achieved first. After the capacity of the compressor210 is minimized, the air mixing damper 154 begins to open (point C inFIG. 17) so that air may be re-heated by the condenser 203.

As the aimed blown out air temperature Tao further rises (point D inFIG. 17), the bypass damper 159 begins to close so that air may beflowed to the condenser 203 side bypassing the evaporator 207. Thiscondition corresponds to dehumidifying operation principally in autumnand winter and in an intermediate time.

As the aimed blown out air temperature Tao further rises (point E inFIG. 17) after then, the operation mode of the automotive airconditioner is changed over from cooling operation to heating operation.In particular, the damper 253 which is the condensing side varying meansis closed to stop the function of the outside condenser 202. Meanwhile,the damper 254 which is the evaporating side varying means is opened tocause the outside evaporator 210 to function.

Then, the discharging capacity of the compressor 201 is raised as theaimed blown out air temperature Tao rises to raise the condensingtemperature at the condenser 203 (points F to G in FIG. 17). It is to benoted that, in the heating condition, when the aimed blown out airtemperature Tao is comparatively low, the bypass damper 159 is held in asomewhat open condition so that dehumidifying operation can be performedsimultaneously.

Then, in maximum heating operation (point H in FIG. 17), the dischargingcapacity of the compressor 201 presents it maximum and the air mixingdamper 154 introduces the entire amount of a flow of air into thecondenser 203. Meanwhile, the bypass damper 159 closes the evaporator207 so that air may be flowed to the condenser 203 side bypassing theevaporator 207. Further, the evaporating side varying means 253 stops,the function of the outside condenser 202 while the evaporating sidevarying means 254 causes the outside evaporator 210 to function.

It is to be noted that, while, in the control described hereinabove withreference to FIG. 17, the condensing side damper 253 and the evaporatingside damper 254 are individually changed over between the fully closedcondition and the fully open condition, pivotal motion of the dampers253 and 254 may otherwise be controlled continuously if necessary.Further, while, in the automotive air conditioner described above, theair mixing damper 154 begins to open after the discharging capacity ofthe compressor 201 has been minimized, the point of time at which theair mixing damper 154 begins to open may be advanced. In other words,the components described above can be changed suitably if necessary.

Further, while, in the automotive air conditioner shown in FIG. 14, thedampers 253 and 254 are employed as condensing side varying means endevaporating side varying means, respectively, alternatively a condensingfan 261 may be provided as condensing side varying means while anevaporating fan 252 is provided as evaporating side varying means asshown in FIG. 18. In particular, the heat exchanging functions of theoutside condenser 202 and the outside evaporator 210 may be varied bycontrolling rotation of the fans 251 and 252, respectively.

It is to be noted that, while the bypass passageway 150 is formedsidewardly of the condenser 203 in the automotive air conditionerdescribed above, alternatively the entire amount of air in the duct 100may pass the condenser 203 as seen from FIG. 20.

A pair of auxiliary heaters 700 and 701 are disposed on the downstreamof the condenser 203 in the duct 100. Each of the auxiliary heaters 700and 701 may be formed from a PCT heater or an electric heater. In theautomotive air conditioner shown in FIG. 20, cooling operation,dehumidifying operation and heating operation are achieved individuallyby controlling flow rates of refrigerant into the evaporator 207 and thecondenser 203 both disposed in the duct 100.

Referring now to FIG. 21, there is shown a refrigerating cycle of theautomotive air conditioner shown in FIG. 20. In the refrigerating cycleshown, the four-way valve 213 changes over, upon energization thereof,the refrigerating passage in such a manner as indicated by a solid line,but changes over, upon deenegization thereof, to such a manner asindicated by a broken line. Further, the outside heat exchanger 202includes a fan 251.

In the present refrigerating cycle, the four-way valve 213 and thesolenoid valves 260 and 261 are suitably changed over to control a flowof refrigerant to achieve various sir conditioning operation. First, acooling operation condition will be described. In this condition, thefour-way valve 213 is energized so that refrigerant discharged from thecompressor 201 is flowed to the outside heat exchanger 202 side by wayof the four-way valve 213 and the check valve 262. Here, the refrigerantmeets with a wind from the fan 251 so that it is condensed in theoutside heat exchanger 202 while remaining in a high temperature, highpressure condition. Meanwhile, the solenoid valve 261 remains closed inthis condition, and accordingly, the refrigerant condensed in theoutside heat exchanger 202 flows into the expanding means 211 and isdecompressed and expanded into mist in a low temperature, low pressurecondition when it passes the expanding means 211. The refrigerant in theform of mist then flows into the evaporator 207, in which it isevaporated, whereupon it takes heat of vaporization away fromconditioning air to cool the air.

Then, the refrigerant evaporated in the evaporator 207 is sucked intothe compressor 210 again by way of the accumulator 212. It is to benoted that, in this instance, since the refrigerant passage iscommunicated at a branching point 264 on the upstream of the accumulator212 with the condenser 203 side by way of the four-way valve 213, thecheck valve 265 positioned on the downstream of the condenser 203 closesthe refrigerating passage in accordance with a difference in pressure,and consequently, substantially no refrigerant will flow into thecondenser 203.

It is to be noted that there is no possibility that part of refrigeranthaving flowed to the condenser 203 side may be liquefied and accumulatedin the condenser 203. This is because refrigerant in the condenser 203is sucked into the compressor 201 by way of the four-way valve 213.

Subsequently, a flow of refrigerant when the automotive air conditioneroperates as a heating apparatus will be described. In this instance, thecompressor 201 and the condenser 203 are communicated with each other byway of the four-way valve 213. Meanwhile, the solenoid valve 260 isclosed to cause refrigerant to flow to a capillary element 266 side.Further, the solenoid valve 261 is opened to cause refrigerant from theoutside heat exchanger 202 to flow to the accumulator 212 side.

Accordingly, upon heating operation, refrigerant put into a hightemperature, high pressure condition by the compressor 201 flows by wayof the four-way valve 213 into the condenser 203, in which it exchangesheat with air from the blower 132. In this instance, since thecondensing temperature is 40° to 60° C. or so, air passing in the duct100 is heated when it passes the condenser 203. The refrigerantcondensed in the condenser 203 is subsequently decompressed andexpanded, when it passes the capillary element 266, into mist of a lowtemperature and a low pressure. The refrigerant mist then flows into theoutside heat exchanger 202 by way of the check valve 265. The outsideheat exchanger 202 acts as an evaporator, and in the outside heatexchanger 202, the refrigerant exchanges heat with sir supplied theretofrom the blower 251 so that it is evaporated. The refrigerant havingpassed the outside heat exchanger 202 can flow to both of the solenoidvalve 261 side and the capillary tube 211 side, but since thecommunication resistance is higher on the capillary tube 211 side, therefrigerant flows, as a result, into the accumulator 212 by way of thesolenoid valve 261 past the branching point 264. It is to be noted that,while the refrigerant passage is communicated with the four-way valve213 at the branching point 264, the refrigerant will not circulate intothe outside heat exchanger 202 again due to a difference in pressure.

Subsequently, a dehumidifying operation condition of the presentautomotive air conditioner will be described. In this instance, thesolenoid valve 260 is opened and the solenoid valve 261 is closed insuch a heating operation condition as described hereinabove.Consequently, refrigerant partially condensed in the outside heatexchanger 202 is decompressed at the capillary tube 211 and flows, inthis condition, into the evaporator 207. Then, in the evaporator 207,the refrigerant will be evaporated to cool air blasted thereto from theblower 132.

Accordingly, in the dehumidifying operation, air is cooled once in theevaporator 207 and then heated in the condenser 203. Consequently, whenthe air passes the evaporator 207, the saturation evaporatingtemperature drops to cause moisture in the air to be condensed andadhere to a surface of the evaporator 207. Then, since the air isre-heated in this condition when it passes the condenser 203, therelative humidity is dropped remarkably, and consequently, gooddehumidification is performed.

FIGS. 22, 23 and 24 are Molliar charts illustrating cooling operation,heating operation and dehumidifying operation, respectively, of therefrigerating cycle shown in FIG. 21. As described above, upon coolingoperation, the outside heat exchanger 202 acts as a condenser while anevaporating action is performed in the evaporator 207. On the otherhand, upon-heating operation, refrigerant is condensed in the condenser203 while the outside heat exchanger 202 acts as an evaporator.

It is to be noted that the difference in evaporating pressure betweenFIGS. 22 and 23 arises from the fact that the temperature of air flowinginto the evaporator 207 upon cooling is higher than the temperature ofair flowing into the outside heat exchanger 202 upon heating.

On the other hand, as seen from FIG. 24, upon dehumidifying operation,condensation of refrigerant is performed by the condenser 203 and theoutside heat exchanger 202 while evaporation of refrigerant is performedby the evaporator 207. In this instance, the enthalpy is higher at theevaporator 207 than at the condenser 203, but since condensation ofmoisture in air proceeds in the evaporator 207, the temperature of airis not lowered very much when it passes the evaporator 207 due to latentheat involved in the condensation of water. Meanwhile, since theenthalpy of the condenser 203 is all used to raise the temperature ofair, the temperature of air having passed both of the evaporator 207 andthe condenser 203 either has a substantially same level or is raised asa result.

Subsequently, control of the temperature of air of the automotive airconditioner upon dehumidifying operation will be described. FIGS. 25, 26and 27 are Mollier charts all illustrating operating conditions upondehumidifying operation, and FIG. 25 shows a Mollier chart upon normaloperation. In the normal operation, the blower 251 is rotated weakly sothat a predetermined amount of air is blasted to the outside heatexchanger 202 to assure heat exchanging at the outside heat exchanger202. As a result, the air temperature lowering capacity of theevaporator 207 substantially coincides with the air temperature raisingcapacity of the condenser 203, and air having passed both of theevaporator 207 and the condenser 203 raises its temperature a little.

FIG. 26 shows a condition wherein it is desired to raise the blown outair temperature in dehumidifying operation. In this instance, the blower251 stops its action in order to reduce the heat exchanging capacity ofthe outside heat exchanger 202. As a result, the condensing capacity isdecreased generally while the condensing pressure is increased. As thecondensing pressure rises, the temperature of air when it passes thecondenser will be raised.

FIG. 27 shows another condition wherein it is desired to lower the blownout air temperature in dehumidifying operation. In this instance, theblower 251 for the outside heat exchanger 202 is rotated at a high speedto raise the condensing capacity of the outside heat exchanger 202. As aresult, the condensing pressure is lowered, and air cooled when itpasses the evaporator 207 will be blown out into the room of theautomobile without being heated very much.

It is to be noted that, in the case of FIG. 27, since the totalcondensing capacity of the outside heat exchanger 202 and the condenser203 is increased, the condensing pressure in the refrigerating cycle islowered, and as a result, also the evaporating pressure at theevaporator 207 is lowered. Consequently, there is the possibility thatfrost may appear on the evaporator 207. Therefore, in this instance, thespeed of rotation of the compressor 201 is controlled so thatdehumidifying operation may continuously proceed without lowering thepressure in the evaporator 207, that is, the sucking pressure of airinto the compressor 201, very much.

Subsequently, defrosting of the outside heat exchanger 202 upon heatingoperation will be described. As described hereinabove, since the outsideheat exchanger 202 functions as an evaporator in heating operation,particularly when the temperature of outside air is low, the temperatureof a surface of the outside heat exchanger 202 becomes lower than thefreezing point and frost adheres to the outside heat exchanger 202.Then, if frost adheres in this manner, the heat exchanging function ofthe outside heat exchanger 202 is deteriorated remarkably so that goodoperation of the refrigerating cycle cannot be achieved and consequentlyheating operation of the condenser 203 is not performed. Thus, in thisinstance, refrigerant in a high temperature, high pressure conditionwill be passed through the outside heat exchanger 202 to melt the frostadhering to the outside heat exchanger 202. In the dehumidifyingoperation, operation of the outside blower 251 is stopped first.Meanwhile, the inside blower 132 is rotated at a low speed. Then, theinside/outside air changing over damper 131 is put into an inside airadmitting condition so that the temperature of blown out air from theduct 100 may not be lowered. Further, power is made availablesimultaneously to the auxiliary heater 700 and 701. In this condition,the solenoid valve 260 is opened while the solenoid valve 261 is closed.Consequently, refrigerant having passed the compressor 201 flows intothe condenser 203 and the outside heat exchanger 202 while it remains ina high temperature, high pressure condition. As a result, thetemperature of the outside heat exchanger 202 rises and frost adheringto the surface of the outside heat exchanger 202 will be melted. Therefrigerant condensed in the outside heat exchanger 202 is thendecompressed and expanded in the capillary tube 211 and then flows intothe evaporator 207. As a result, the temperature of air in the duct 100becomes low, but since, in this condition, the amount of a wind of theblower 132 is small and the auxiliary heaters 700 and 701 can work tothe utmost, remarkable deterioration of the blown out air temperaturecan be prevented.

Further, in order to accomplish defrosting of the outside heat exchanger202 in a short period of time, the compressor 201 has a capacity as highas possible and the invertor thereof has a frequency as high aspossible.

It is to be noted that, when defrosting operation is proceeding in thismanner, a lamp may be lit so that this may be recognized by a passengerof the automobile.

Further, when operation of the automotive air conditioner is automaticoperation, changing over between heating operation and defrostingoperation is performed in accordance with the following conditions:

(1) The temperature of the outside heat exchanger 202 is lower by 10° C.or more than the temperature of outside air;

(2) The temperature of the outside heat exchanger 202 is lower than -3°C. or so; and

(3) Heating operation has continued for longer than a predeterminedperiod of time (60 minutes).

Whether or not defrosting is required is judged in accordance with theconditions.

FIG. 28 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner adopts athree-way valve 269 in place of the four-way valve 213 of the automotiveair conditioner shown in FIG. 21. In addition, a solenoid valve 268 isdisposed in a cooling pipe adjacent the branching point on the upstreamof the accumulator 212.

Upon cooling operation, the three-way valve 269 is changed over to aposition indicated by a solid line so that refrigerant discharged fromthe compressor 201 may be introduced to the outside heat exchanger 202.In this instance, the outside heat exchanger 202 acts as a condenser,and refrigerant decompressed and expanded in the capillary tube 211 isthen supplied to the evaporator 207. The refrigerant evaporated in theevaporator 207 is fed back to the accumulator 212 side past thebranching point 264. The solenoid valve 268 opens the refrigerant pipeupon cooling operation. Consequently, also refrigerant accumulated inthe condenser 203 is supplied, due to sucking action of the compressor201, from the refrigerant pipe to the compressor 201 side by way of thesolenoid valve 268 and the branching point 264. In this instance, thepressure of refrigerant in the condenser 203 is decreased suddenly sothat also the evaporating temperature of the refrigerant is lowered.Consequently, immediately after starting of cooling operation, alsorefrigerant accumulated in the condenser 203 is evaporated thereby tocomplement the cooling capacity. On the other hand, upon heatingoperation, the three-way valve 269 is changed over so that refrigerantdischarged from the compressor 201 is now introduced into the condenser203. Further, the solenoid valve 260 is closed so that refrigerantcondensed in the condenser 203 is supplied to the outside heat exchanger202 by way of the capillary element 266. Meanwhile, the solenoid valve261 is opened so that refrigerant evaporated in the outside heatexchanger 202 is sucked from the solenoid valve 261 toward theaccumulator 212 side. In this instance, the solenoid valve 268 is in aclosed condition, and refrigerant discharged from the compressor 201 isprevented from being short-circuited to be sucked to the accumulator 212side.

Upon dehumidifying operation, the three-way valve 296 introducesrefrigerant discharged from the compressor 201 to the condenser 203.Meanwhile, the solenoid valve 260 opens the refrigerant passage so thatrefrigerant of a high pressure is supplied from the condenser 203 to theoutside heat exchanger 202. Then, the solenoid valve 261 is closed sothat refrigerant condensed by the condenser 203 and the outside heatexchanger 202 is supplied to the evaporator 207 by way of the capillarytube 211.

It is to be noted that actions in defrosting operation and dehumidifyingoperation of the automotive air conditioner of FIG. 28 are similar tothose of the automotive air conditioner shown in FIG. 21.

FIG. 29 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner employs a pairof solenoid valves 270 and 271 in place of the three-way valve 269 ofthe automotive air conditioner of FIG. 28. Actions in cooling operation,heating operation and dehumidifying operation are similar to those ofthe automotive air conditioner of FIG. 28.

FIG. 30 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner employs asingle three-way valve 272 in place of the two solenoid valves 270 and268 of the automotive air conditioner of FIG. 29.

FIG. 31 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner is constructedsuch that the operation thereof between cooling operation and heatingoperation is performed by changing over of the four-way valve 213.

In particular, upon cooling operation, the four-way valve 213 introduceshigh pressure refrigerant discharged from the compressor 201 into theoutside heat exchanger 202. The refrigerant condensed in the outsideheat exchanger 202 is decompressed and expanded in the capillary tube211 and supplied to the evaporator 207. It is to be noted that a backflow of the refrigerant to the condenser 203 side then is prevented by acheck valve 273. Then, the refrigerant evaporated in the evaporator 207is sucked into the compressor 201 by way of the accumulator 212.

On the other hand, upon heating, the four-way valve 213 is changed overso that refrigerant discharged from the compressor 201 is supplied tothe condenser 203. Then, the refrigerant condensed in the condenser 203is decompressed and expanded when it passes the capillary element 266,and after then, it flows to the branching point 274 by way of the checkvalve 273. Most of the refrigerant coming to the branching point 274flows to the outside heat exchanger 202 side due to a difference inpressure. Meanwhile, part of the refrigerant flows to the evaporator 207by way of the capillary tube 211. Then, the refrigerant evaporated inthe outside heat exchanger 202 and the evaporator 207 is supplied to theaccumulator 213 and then fed back to the compressor 201.

In such heating operation, refrigerant will not flow much to theevaporator 207 side due to a resistance of the capillary tube 211.However, some refrigerant is supplied to the evaporator 207, at whichpart of the refrigerant is evaporated. Consequently, even duringheating, some dehumidifying operation is achieved.

FIG. 32 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, changingover of a cycle is performed by the single four-way valve 213 and asingle on/off solenoid valve 290. Upon cooling operation, the four-wayvalve 213 is changed over to a position indicated by a solid line inFIG. 32 and the solenoid valve 290 is opened. As a result, refrigerantdischarged from the compressor 201 is condensed in the outside heatexchanger 202 and then decompressed and expanded in the capillary tube211, whereafter it flows into the evaporator 207. Then, the refrigerantcools air by an evaporating action of the evaporator 207. On the otherhand, upon heating, the four-way valve 213 is changed over to anotherposition indicated by a broken line in FIG. 32, and also the solenoidvalve 290 is put into an open condition. As a result, refrigerantdischarged from the compressor 201 is condensed in the condenser 203 andthen decompressed and expanded in the capillary 266. After then, therefrigerant passes the check valve 273 and then flows mainly to theoutside heat exchanger 202 side due to a difference in pressure.Meanwhile, part of the refrigerant flows into the evaporator 207 by wayof the capillary tube 211. Then, the refrigerant having passed theoutside heat exchanger 202 and the evaporator 207 is collected into theaccumulator 212 and then fed back into the compressor 201. In thiscondition, since some refrigerant flows into the evaporator 207,dehumidifying operation is performed suitably upon heating.

Further, when dehumidifying operation is to be performed, the four-wayvalve 213 is changed over similarly as upon heating operation, describedabove, and the solenoid valve 290 is opened and closed at suitabletimings. When the solenoid valve 290 closes the refrigerant passage,refrigerant flows into the evaporator 207 by way of the capillary tube211 so that the cooling capacity of the evaporator 207 is increased.Consequently, the dehumidifying function of the evaporator 207 isincreased. Then, a required dehumidifying amount is obtained by suitablychanging over the opening/closing operation of the solenoid valve 290 ata suitable duty ratio. Upon dehumidifying operation, the solenoid valve290 may be held closed normally.

FIG. 33 shows a yet further automotive air conditioner according to thepresent invention. Upon cooling operation, the four-way valve 213 ischanged over to a position indicated by a solid line in FIG. 33 and thesolenoid valve 203 opens its refrigerant pipe while the solenoid valve294 closes its refrigerant pipe. Meanwhile, the solenoid valve 291 opensits refrigerant pipe. It is to be noted that the solenoid valve 292performs opening and closing operations of the refrigerant pipe suitablyin accordance with a required cooling capacity. Accordingly, in thiscondition, refrigerant discharged from the compressor 201 flows into theoutside heat exchanger 202 by way of the four-way valve 213 and thesolenoid valve 293 and is condensed in the outside heat exchanger 202.After then, the refrigerant passes the solenoid valve 291 and isdecompressed and expanded in the capillary tube 211, whereafter it isevaporated in the evaporator 207. After then, it passes the accumulator212 and is fed back to the compressor 201.

Upon heating operation, the four-way valve 213 is changed over toanother position indicated by a broken line in FIG. 33 and the solenoidvalve 291 closes its refrigerant pipe. Meanwhile, the solenoid valve 292opens its refrigerant pipe; the solenoid valve 293 opens its refrigerantpipe: and the solenoid valve 294 closes its refrigerant pipe. As aresult, refrigerant discharged from the compressor 201 flows into thecondenser 203 by way of the four-way valve 213 and is then decompressedand expanded in the capillary element 266, whereafter it is evaporatedin the outside heat exchanger 202. After then, it is fed back to thecompressor 201 by way of the solenoid valve 293, the four-way valve 213and the accumulator 212.

Subsequently, dehumidifying operation will be described. In thisinstance, both of the solenoid valves 291 and 294 are opened. As aresult, refrigerant discharged from the compressor 201 is divided into aflow which then is liquefied in the condenser 203 and flows to theevaporator 207 by way of the capillary 211 and another flow which thenflows by way of the solenoid valve 294 into the outside heat exchanger202, in which it is liquefied, whereafter it flows to the evaporator 207by way of the solenoid valve 291 and the capillary tube 211. Inparticular, condensation of refrigerant is performed in parallel by thecondenser 203 and the outside heat exchanger 202. Then, the refrigerantevaporated in the evaporator 207 flows into the accumulator 212 by wayof the refrigerant pipe.

Here, upon such dehumidifying operation, the condensing pressure can becontrolled by varying the heat exchanging capacity of the outside heatexchanger 202. The capacity control of the outside heat exchanger 202 isperformed by varying the amount of blown out air by the blower 251.Alternatively, a damper for the outside heat exchanger 202 may beprovided in place of the blower 251. Further, the opening and closingtimes of the solenoid valve 294 may be controlled to control thecondensing pressure, that is, the blown out air temperature.

FIG. 34 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, coolingoperation, heating operation and dehumidifying operation are selectivelyperformed by suitably changing over solenoid valves 295, 296 and 297.First, cooling operation will be described. In this instance, thesolenoid valve 295 closes its refrigerant passage while the solenoidvalve 296 opens its refrigerant passage and also the solenoid valve 297opens its refrigerant passage. Further, the four-way valve 213 ischanged over to a position indicated by a broken line. Consequently,refrigerant discharged from the compressor 201 flows by way of thefour-way valve 213 into the outside heat exchanger 202, in which itexchanges heat with outside air so that it is condensed. The refrigerantthen flows into the solenoid valve 296 by way of the check valve 280 andthen passes the capillary element 266, whereupon it is decompressed andexpanded. After then, the refrigerant flows into the evaporator 207, inwhich it takes heat of vaporization away from air so that is itevaporated. After then, the refrigerant flows into the accumulator 212by way of the solenoid valve 297 and the four-way valve 213.

On the other hand, upon heating, the solenoid valve 295 opens itsrefrigerant pipe while the solenoid valve 296 closes its refrigerantpipe and also the solenoid valve 297 closes its refrigerant pipe.Further, the four-way valve 213 is changed over to another positionindicated by a solid line in FIG. 34. Consequently, upon heatingoperation, refrigerant discharged from the compressor 201 successivelypasses the four-way valve 213, the check valve 281 and the solenoidvalve 295 and is then condensed in the condenser 203. After then, therefrigerant is decompressed and expanded when it passes the capillarytube 211, and then flows into the outside heat exchanger 202 by way ofthe check valve 282. Then, the refrigerant is evaporated in the outsideheat exchanger 202 and is fed back into the compressor 201 by way of thefour-way valve 213 and the accumulator 212.

Subsequently, dehumidifying operation will be described. In thisinstance, the solenoid valve 295 is opened while the solenoid valve 296is closed and also the solenoid valve 297 is closed. Then, the four-wayvalve 213 is changed over to the position indicated by the broken linein FIG. 34. Accordingly, refrigerant discharged from the compressor 201flows by way of the four-way valve 213 into the outside heat exchanger202, in which it is condensed. Further, the refrigerant flows by way ofthe check valve 280 and the solenoid valve 295 into the compressor 203,in which it is condensed. Then, when the refrigerant passes thecapillary tube 211, it is decompressed and expanded into a lowtemperature, low pressure condition and then flows, in this condition,into the evaporator 207. The refrigerant is evaporated in the evaporator207 and then fed back into the compressor 201 by way of the solenoidvalve 297, the four-way valve 313 and the accumulator 212. Accordingly,in the automotive air conditioner shown in FIG. 34, upon dehumidifyingoperation, condensation of refrigerant is performed by the outside heatexchanger 202 and the condenser 203, and the blown out air temperatureis controlled by controlling the amount of blown out air by the blower251 to control the heat exchanging capacity of the outside heatexchanger 202 to vary the condensing pressure of the condenser 203.

In particular, in the automotive air conditioner shown in FIG. 34, upondehumidifying operation, refrigerant flows first into the outside heatexchanger 202 and then into the condenser 203. On the other hand, in theautomotive air conditioner shown in FIG. 21, refrigerant flows firstinto the condenser 203 and then into the outside heat exchanger 202.Here, in case refrigerant flows first into the condenser 203, therefrigerant having high superheat immediately after discharged from thecompressor 201 flows into the condenser 203, and consequently, the blownout air temperature from the condenser 203 becomes higher anddehumidification having some heating effect can be performed.

FIG. 35 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, theoperation is changed over among cooling operation, heating operation anddehumidifying operation by means of the four-way valve 213 and asolenoid valve 298.

First, in cooling operation, the four-way valve 213 is changed over to aposition indicated by a broken line in FIG. 35, and the solenoid valve298 opens its passage. As a result, refrigerant discharged from thecompressor 201 flows by way of the four-way valve 213 into the outsideheat exchanger 202, in which it is condensed. Then, the condensedrefrigerant passes the check valve 283 and the solenoid valve 298 and isthen decompressed and expanded in the capillary tube 211. After then,the refrigerant is evaporated in the evaporator 207 and is fed back intothe compressor 201 by way of the accumulator 212.

On the other hand, upon heating operation, the four-way valve 213 ischanged over to another position indicated by a solid line in FIG. 35,and the solenoid valve 298 closes its refrigerant pipe. Accordingly,refrigerant discharged from the compressor 201 flows by way of thefour-way valve 213 into the condenser 203, in which it is condensed.After then, the refrigerant flows by way of the check valve 294 into thecapillary element 266, in which it is decompressed and expanded,whereafter it flows into the outside heat exchanger 202. Then, therefrigerant is evaporated in the outside heat exchanger 202 and then isfed back into the compressor 201 by way of the four-way valve 213 andthe accumulator 212.

Upon dehumidifying operation, the four-way valve 213 is changed oversimilarly to the position indicated by the solid line in FIG. 35, andthe solenoid valve 298 opens its refrigerant pipe. Consequently,refrigerant discharged from the compressor 201 flows into the condenser203, in which it is condensed and liquefied. The refrigerant liquefiedin the condenser 203 is then divided into a flow which flows into theoutside heat exchanger 202 by way of the capillary 266 and another flowwhich flows into the evaporator 207 by way of the solenoid valve 298 andthe capillary tube 211. Thus, the refrigerant is evaporated in theoutside heat exchanger 202 and the evaporator 207. The thus evaporatedrefrigerant is collected into the accumulator 212 again and is then fedback into the compressor 201. In this manner, upon dehumidifyingoperation, refrigerant flows in parallel through the outside heatexchanger 202 and the evaporator 207, and control of the dehumidifyingcapacity then is achieved by controlling the blower 251 to vary the heatexchanging capacity of the outside heat exchanger 202.

FIG. 36 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner is amodification to the automotive air conditioner shown in FIG. 35 in thatit additionally includes a refrigerant pipe which interconnects, upondehumidifying operation, the downstream of the outside heat exchanger202 and the evaporator 207 and further includes a solenoid valve 299 andanother solenoid valve 289 for controlling flows of refrigerant.Operations upon cooling operation and heating operation are similar tothose of the refrigerating cycle described hereinabove with reference toFIG. 35. Upon dehumidifying operation, the solenoid valve 299 is openedwhile the solenoid valve 289 is closed, and in this instance,refrigerant is evaporated in both of the outside heat exchanger 202 andthe evaporator 207 similarly as in the refrigerating cycle shown in FIG.35. However, in case, upon dehumidifying operation, the solenoid valve298 is closed and also the solenoid valve 299 is closed while thesolenoid valve 289 is opened, refrigerant flows in series through theoutside heat exchanger 202 and the evaporator 207. In particular, inthis condition, refrigerant discharged from the compressor 201 flows byway of the four-way valve 213 into the condenser 203, in which it iscondensed. The thus condensed refrigerant flows by way of the checkvalve 284 into the capillary element 266, in which it is decompressedand expanded, whereafter it is evaporated in the outside heat exchanger202. After then, the refrigerant flows by way of the solenoid valve 289into the evaporator 207, in which it is evaporated similarly. Then, thethus evaporated refrigerant is fed back into the compressor 201 again byway of the accumulator 212. In this manner, the cycle shown in FIG. 36can be changed over, upon dehumidifying operation, between a conditionwherein refrigerant condensed by the condenser 203 is admitted inparallel into both of the evaporator 207 and the outside heat exchanger202 and another condition wherein the outside heat exchanger 202 and theevaporator 207 are disposed in series so that refrigerant is evaporatedin both of them.

FIG. 37 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, theevaporator 207 and the outside heat exchanger 202 are also disposed inseries upon dehumidifying operation, but the order in arrangement ofthem is reverse to that in the automotive air conditioner shown in FIG.36. In particular, while, in the refrigerating cycle shown in FIG. 36,the outside heat exchanger 202 and the evaporator 207 are connected Inseries upon dehumidifying operation such that the outside heat exchanger202 may be positioned on the Upstream side, in the refrigerating cycleshown in FIG. 37, the evaporator 207 and the outside heat exchanger 202are connected such that the evaporator 207 may be positioned on theupstream side of the outside heat exchanger 202.

Subsequently, the refrigerating cycle shown in FIG. 37 will bedescribed. First, upon cooling operation, the four-way valve 213 ischanged over to a position indicated by a broken line in FIG. 37, andthe solenoid valve 288 closes its refrigerant passage while the solenoidvalve 298 opens its refrigerant passage. Accordingly, refrigerantdischarged from the compressor 201 flows by way of the four-way valve213 into the outside heat exchanger 202, in which it is condensed. Thethus liquefied refrigerant flows through the check valve 213 and thesolenoid valve 298 into the capillary tube 211, and it is decompressedand expanded when it passes the capillary tube 211. Then, the,refrigerant is evaporated in the evaporator 207 and then flows into theaccumulator 212 by way of the four-way valve 213, whereafter it is fedback into the compressor 201.

On the other hand, upon heating operation, the four-way valve 213 ischanged over to another position indicated by a solid line in FIG. 37,and the solenoid valve 288 is opened while the solenoid valve 298 isclosed. Accordingly, in this condition, refrigerant discharged from thecompressor 201 flows into the condenser 203 by way of the four-way valve213. Then, the refrigerant condensed in the condenser 203 flows into thecapillary element 266 by way of the solenoid valve 288 and isdecompressed and expanded when it passes the capillary element 266.After then, the refrigerant is evaporated in the outside heat exchanger202, and then the thus evaporated refrigerant flows into the accumulator212 by way of the four-way valve 213, whereafter it is fed back to thecompressor 201 again.

Further, upon dehumidifying operation, the four-way valve 213 is changedover to the position indicated by the solid line in FIG. 37 and thesolenoid valve 298 is opened while the solenoid valve 288 is closed.Accordingly, refrigerant discharged from the compressor 201 flowsthrough the four-way valve 213 into the condenser 203, in which it iscondensed and liquefied. After then, the refrigerant flows through thesolenoid valve 298 into the capillary tube 211 and is decompressed andexpanded when it passes the capillary tube 211. After then, therefrigerant flows into the evaporator 207, in which it is evaporated.After then, the refrigerant flows through the check valve 286 into theoutside heat exchanger 202, in which it is further evaporated. Then, therefrigerant is fed back into the compressor 201 by way of the four-wayvalve 213 and the accumulator 212. Accordingly, upon such dehumidifyingoperation, refrigerant is evaporated in both of the evaporator 207 andthe outside heat exchanger 202, and besides the evaporator 207 islocated on the upstream side of the outside heat exchanger 202.

Here, it is suitably selected in accordance with the necessity, when theoutside heat exchanger 202 and the evaporator 207 are disposed in seriesupon dehumidifying operation, which one of them is located on theupstream side. However, in a cycle which includes the accumulator 212,there is no significant difference in function whichever one of them isdisposed on the upstream side. In particular, since the outside heatexchanger 202 and the evaporator 207 do not present differentevaporating pressures while the temperatures of air admitted into themare different from each other, the evaporating capacity of theevaporator 207 is equal whether it is located on the upstream side or onthe downstream side.

FIG. 38 shows a yet further automatic air conditioner according to thepresent invention. In the present automotive air conditioner, theevaporator 207 includes a damper 159 having a variable capacity. Uponcooling operation and upon dehumidifying operation, the damper 159 opensthe duct 100 so that air may be admitted into the evaporator 207, butupon heating operation, the damper 159 is closed so that air may not beadmitted into the evaporator 207. Meanwhile, a flow of refrigerant tothe condenser 203 is changed over by the three-way valve 213 and thesolenoid valve such that refrigerant may be condensed, upon heatingoperation and upon dehumidifying operation, in the condenser 203, butrefrigerant may flow, upon cooling operation, directly to the outsideheat exchanger 202 bypassing the condenser 203.

FIG. 39 shows a yet further automatic air conditioner according to thepresent invention. While a flow of refrigerant is changed over, in theautomatic air conditioner shown in FIG. 38, between the condenser 203side and the other side bypassing the condenser 203, in the automaticair conditioner shown in FIG. 39, the capacity of the condenser 203 ischanged over by means of the damper 154. In particular, upondehumidifying operation and upon heating, the damper 154 opens the duct100 so that air may be admitted into the condenser 203, but upon coolingoperation, the damper 154 is closed so that air may not be admitted intothe condenser 203. However, even during cooling operation, when thedamper 154 operates as an air mixing damper for varying the blown outair temperature, the damper 154 opens its passage in response to anecessary blown out air temperature so that part of air may bere-heated.

FIG. 40 shows a yet further automatic air conditioner according to thepresent invention. The present automatic air conditioner includes,similarly to the automatic air conditioner described hereinabove withreference to FIG. 13, the dampers 154 and 159 for both of the condenser203 and the evaporator 207, respectively. However, the present automaticair conditioner is different in circuit of the refrigerating cycle fromthe automatic air conditioner shown in FIG. 13. A flow of refrigerant iscontrolled in the refrigerating cycle by changing over of the solenoidvalves 260 and 261. Upon heating operation, the solenoid valve 260 isopened while the solenoid valve 261 is closed. Consequently, refrigerantdischarged from the compressor 201 flows through the condenser 203 andthe solenoid valve 260 into the outside heat exchanger 202, in which itis evaporated. It is to be noted that, in this instance, the condenser203 does not perform a condensing action in principle as the damper 154is held closed. Then, the refrigerant condensed in the outside heatexchanger 202 is decompressed and expanded when it passes the capillarytube 211, and consequently, the refrigerant in a low temperature, lowpressure condition flows into the evaporator 207. In this condition, thedamper 159 holds the duct 100 in a closed condition, and consequently,air from the blower 132 flows into the evaporator 207 to evaporate therefrigerant. The thus evaporated refrigerant is then fed back into thecompressor 201 by way of the accumulator 212.

On the other hand, upon heating operation, the solenoid valve 260 isclosed while the solenoid valve 261 is opened. In this condition,refrigerant discharged from the compressor 201 flows into the condenser203, in which it is condensed. In particular, in this condition, thedamper 154 is opened so that air may be admitted into the condenser 203.After then, the refrigerant is decompressed and expanded when it passesthe capillary element 266, and is then evaporated in the outside heatexchanger 202. The thus evaporated refrigerant is fed back into thecompressor 201 by way of the solenoid valve 261 and the evaporator 207.In this condition, the evaporator 207 is closed by the damper 159, andconsequently, refrigerant is little evaporated in the evaporator 207.

Subsequently, upon dehumidifying operation, the solenoid valve 260 isopened while the solenoid valve 261 is closed. Accordingly, refrigerantdischarged from the compressor 201 flows into the condenser 203, inwhich it is condensed. The refrigerant then flows through the solenoidvalve 260 into the outside heat exchanger 202, also which accomplishes acondensing function to condense the refrigerant. After then, therefrigerant is decompressed and expanded when it passes the capillarytube 211, and is then evaporated in the evaporator 207. Then, therefrigerant thus evaporated in the evaporator 207 is fed back to thecompressor 201 by way of the accumulator 212. In this condition, theevaporating capacity of the evaporator 207 and the condensing capacityof the condenser 203 are variably controlled by adjusting the circuitsof the dampers 159 and 154, respectively. Further, in order to controlthe condensing capacity of the condenser 203, the condensing capacitycontrol of the outside heat exchanger 202 by control of the amount ofair of the fan 151 for the outside heat exchanger 202 or the like may beemployed additionally similarly as in the case of the automotive airconditioner shown in FIG. 21.

As described so far, with the automotive air conditioner of the presentinvention, the operation can be changed over among cooling operation,heating operation and dehumidifying operation by controlling the routesof flows of refrigerant through the compressor 201, the outside heatexchanger 202, the condenser 203, the evaporator 207 and thedecompressing or expanding means 211. Further, according to the presentinvention, further advantageous air conditioning operation describedbelow can be achieved by suitably controlling changing over particularlybetween a dehumidifying operation condition and a heating operationcondition.

In case fogging of the windshield of the automobile is forecast ordetected in a heating operation condition, the condition of thewindshield can be prevented well by changing over the flow ofrefrigerant into that of a dehumidifying operation condition.Particularly upon dehumidifying operation, since the drop in temperatureof blown out air at the evaporator 207 is greater than the rise at thecondenser 203 as described above, dehumidification having somewhatheating effect can be achieved. Accordingly, even if the operation ischanged over from a heating operation condition to a humidifyingoperation condition, the temperature of blown out air will not belowered remarkably, and consequently, good heating can be achieved.

Meanwhile, in a humidifying operation condition, since the evaporator207 performs an evaporating action, particularly when the temperature ofair sucked into the evaporator 207 is low as in winter, there is thepossibility that the evaporator 207 may be frozen. Thus, in such a case,otherwise possible freezing of the evaporator 207 can be prevented wellby changing over the operation from the dehumidifying operation to aheating operation.

FIG. 41 shows a flow chart when the operation is changed over from aheating operation condition to a dehumidifying operation condition. Thepresent flow chart is used to control changing over of the solenoidvalves of the refrigerating cycle described hereinabove. After operationis started at step 440, it is judged at step 441 whether or not the airconditioner switch 305 is on or off. In case the air conditioner switch305 is on, it is then judged at step 442 whether or not therefrigerating cycle is in an operation condition wherein it blows outonly a weak wind or in an air conditioning operation condition whereinthe compressor 201 is operating. If an air conditioning operationcondition is judged at step 442, judgment of a cooling operationcondition, a dehumidifying operation or a heating operation condition isperformed at step 443.

As described hereinabove, in any of the refrigerating cycles, in acooling operation condition, refrigerant discharged from the compressor201 is condensed in the outside heat exchanger 202, and thendecompressed and expanded, whereafter it is supplied into the evaporator207. Then, the refrigerant takes heat of vaporization away from air inthe evaporator 207 to cool the air. On the other hand, in a heatingoperation condition, refrigerant discharged from the compressor 201flows into the condenser 203, in which it radiates heat of condensationinto air to heat the air. After then, the refrigerant is decompressedand expanded, and then it is evaporated in the outside heat exchanger202 and fed back into the compressor 201 again.

Upon dehumidifying operation, the manner of use of the outside heatexchanger 202 is different among the different refrigerating cycles, butthe condenser 203 performs a condensing function to radiate heat ofcondensation into air to heat the air. Further, the evaporator 207performs an evaporating action to cool air by heat of vaporization tocondense moisture from within the air. Then, the outside heat exchanger202 acts as an evaporator or a condenser depending upon a circuit of therefrigerating cycle. Further, as described already, a flow ofrefrigerant flowing to the outside heat exchanger 202 may flow in seriesto the condenser 203 or in parallel to the condenser 203. In particular,in a first condition, refrigerant discharged from the compressor 201first flows into the condenser 203 and then into the outside heatexchanger 202 so that it may undergo a condensing action by both ofcondenser 203 and the outside heat exchanger 202, whereafter it flowsinto the evaporator 207 by way of the capillary tube 211. On the otherhand, in a second condition, refrigerant discharged from the compressor203 is supplied in parallel into both of the condenser 208 and theoutside heat exchanger 202, and then the refrigerant condensed in bothof the condenser 203 and the outside heat exchanger 202 is supplied intothe evaporator 207 by way of the capillary tube 211.

Further, also when the outside heat exchanger 202 acts as an evaporatorupon dehumidifying operation, similarly two cases are availableincluding a first case wherein refrigerant flows in series and a secondcase wherein refrigerant flows in parallel. In particular, in the firstcase, refrigerant condensed in the condenser 203 flows, After passingthe capillary tube 212, in series through the outside heat exchanger 202and the evaporator 207 such that an evaporating action is achieved byboth of the outside heat exchanger 202 and the evaporator 207,whereafter the refrigerant is sucked into the compressor 201.Particularly in this instance, either the evaporator 207 may be locatedon the upstream side of the outside heat exchanger 202 or the outsideheat exchanger 202 may be located on the upstream side of the evaporator207.

Meanwhile, in the second case, liquid refrigerant condensed in thecondenser 203 is supplied, after passing the capillary tube 211, inparallel to both of the outside heat exchanger 202 and the evaporator207.

In the present flow chart of FIG. 41, it is judged, at step 444, inaccordance with a changed over condition of the inside/outside airchanging over damper 131 whether a heating operation or a dehumidifyingoperation should be performed in a heating operation condition. Then, incase an outside air admitting condition is detected at step 444, theheating operation condition is maintained. This is because, normally inan outside air introducing condition, ventilation of the room of theautomobile is performed and the windshield is not likely fogged. In caseit is judged at step 444 that the inside/outside air changing overdamper 131 is in an inside air admitting condition, it is judgedsubsequently at step 445 whether or not a cancelling switch is on oroff. The cancelling switch is provided, though not shown, on the controlpanel for preventing, by manual operation thereof, operation of theautomatic air conditioner from automatically changing over from aheating operation condition to dehumidifying operation. However, in casethe cancelling switch is on, even if it is forecast at step 444 that thewindshield may be fogged, heating operation will still be continued.Only when the cancelling switch is not on, dehumidifying operation isperformed in case fogging of the windshield is forecast at step 444.Preferably, the dehumidifying operation here is dehumidifying operationhaving some heating effect. This is achieved by lowering, in therefrigerating cycle in which the outside heat exchanger acts as acondenser, the heat exchanging function of the outside heat exchanger.It is to be noted that such dehumidifying operation having some heatingeffect will be hereinafter described. It is to be noted that, while, inthe flow chart of FIG. 41, a fogged condition of the windshield isjudged in accordance with a changing over condition of theinside/outside changing over damper 131, changing over may otherwise beperformed in accordance with a blowing out mode or an outside aircondition as seen from the flow chart shown in FIG. 42. In particular,even if an outside air admitting condition is detected at step 444, ifit is judged at step 446 that air flows to the def spit hole 146, thenit is determined that the passenger requires dehumidification, andconsequently, the operation is changed over to the dehumidifyingoperation side. It is to be noted that judgment of a mode at step 444and judgment of changing over between spit holes at step 446 aredifferent from each other as described subsequently. In particular, thejudgment of a mode at step 444 is made principally based on a necessaryblown out air temperature Tao while changing over of a mode at step 446is performed by selection of the passenger. At step 447, it is judgedwhether or not the temperature of outside air is equal to or higher than0° C. Here, in case it is judged that the outside air temperature islower than 0° C., heating operation is selected because, otherwise ifdehumidifying operation is performed, then there is the possibility thatthe evaporator 207 may be frozen. Then, when the outside air temperatureis equal to or higher than 0° C. and there is no possibility that theevaporator 207 may be frozen, dehumidifying operation is selected. TheDEF mode at step 446 mentioned above denotes a condition wherein airflows to the def spit hole 146 and includes not only a case wherein theentire amount of air flows to the def spit hole 146 but also anothercase wherein air flows to both of the def spit hole 146 and the footspit hole 145. FIG. 43 shows another flow chart of changing over betweenheating operation and dehumidifying operation. In the flow chart of FIG.43, fogging of the windshield is judged at step 448. The judgment isperformed using a dewing sensor not shown. The dewing sensor identifiesfrom a temperature of a glass portion and a humidity of air whether ornot the surface of the glass is lower than a dew point of moisture inthe air in order to forecast occurrence of fogging. Then, in caseoccurrence of fogging is not detected or forecast at step 448, theautomotive air conditioner enters heating operation. In case occurrenceof fogging is forecast at step 448, a temperature of outside air isdetected at step 447, and if the outside air temperature is equal to orhigher than 0° C., then dehumidifying operation having some heatingeffect is selected. In this instance, the inside/outside air changingover damper is put into an inside air admitting condition in order toachieve a high heating efficiency while the damper 141 is opened so thatwarm air may advance from the def spit hole 146 toward the windshield.In case a temperature of outside air equal to or higher than 0° C. isdetected at step 447, heating operation is selected in order to preventfreezing of the evaporator 207. However, since this condition is acondition wherein fogging of the windshield is forecast, theinside/outside air changing over damper 131 is put into the outside airadmitting condition. Further, the damper 141 opens the def passage 146so that air warmed by heating operation may be blown out from the defspit hole 146 toward the windshield. In case it is judged at step 447that the outside air temperature is equal to or higher than 0° C.,dehumidifying operation having some heating effect is performed. In thisinstance, the inside/outside air changing over damper 131 is changedover to the inside air admitting condition in order to lower the heatingload. Further, the def spit hole 146 is opened so that fogging of thewindshield may be prevented well. FIG. 44 is a flow chart illustrating afurther control for the prevention of fogging of the windshield. In thepresent flow chart, detection of occurrence of fogging is executed inaccordance with the position of the inside/outside air changing overdamper 131 (step 444). Then, in case an inside air admitting conditionis judged at step 444, since this is a condition wherein fogging of thewindshield is forecast, an actual situation of the windshield is judgedat step 448. Then, in case it is detected that the windshield isactually fogged or is entering into a fogged condition, dehumidifyingoperation having some heating effect is selected. On the contrary iffogging of the windshield is not detected at step 448, even if an insideair admitting condition is judged at step 444, heating operation will becontinued. FIG. 45 shows a flow chart of another example of controllingchanging over between dehumidifying operation having some heating effectand heating operation. In the present example, a changed over positionof the inside/outside air changing over damper 131 is judged at step 444and the changing over is controlled in accordance with the judgmentsimilarly as in the flow chart described hereinabove. However, even whenan inside air admitting condition is detected at step 444, when thecancelling switch is in an on-state, heating operation is continued(step 445) similarly as in the flow chart shown in FIG. 42. Further, inthe flow chart shown in FIG. 45, a step 449 is added so that an elapsedtime after the inside/outside changing over damper 131 has been changedover to the inside air admitting condition may be judged. This isbecause, even if the inside/outside air changing over damper 131 ischanged over to the inside air admitting condition, this will notimmediately result in fogging of the windshield. Thus, in case it isjudged at step 449 that the inside air admitting condition has continuedfor a predetermined period of time, for example, for 1 to 3 minutes orso, dehumidifying operation having some heating effect is entered. Onthe other hand, in case it is detected at step 449 that the inside airadmitting condition has continued but for a period of time shorter thanthe predetermined period of time, for example, 1 to 3 minutes, heatingoperation will be continued. This is because, depending upon a drivingcondition of the automobile, the automotive air conditioner is sometimesused in such a manner that the admitting time of inside air comes to anend after a comparatively short period of time such that the inside airadmitting condition may be entered and continued only while theautomobile is driving, for example, in a tunnel. It is to be noted that,while, in the flow chart shown in FIG. 45, dehumidifying operationhaving some heating effect is performed if dehumidification is necessarywhen heating operation is selected at step 443, alternativelydehumidifying operation having some heating effect and heating operationmay be performed alternately as seen from FIG. 46. In this instance,such alternate operation may be performed at intervals of 5 to 10minutes or so. Consequently, even upon dehumidifying operation, heatingof the room of the automobile can be performed well. A flow chart ofcontrol wherein, when dehumidifying operation is selected at step 443,the operation is changed over to heating operation is shown in FIG. 47.This is because, since the evaporator 207 operates, in a dehumidifyingoperation condition, so that cool air is normally admitted into theevaporator 207 from outside the automobile as described above, there isthe possibility that the evaporator 207 may be frozen. If the evaporator207 is frozen, then the ventilation resistance is increased and the heatexchanging efficiency is deteriorated. Therefore, in the flow chart ofFIG. 47, a frozen condition of the evaporator 207 is judged at step 450.The judgment at step 450 determines a frozen condition of the evaporator207 when the detection temperature signal from the temperature sensorfor detecting a temperature of the surface of the evaporator 207 islower than 0° C. and the temperature of air having passed the evaporator207 is lowered to 0° C. or so. If a frozen condition of the evaporator207 is not determined at step 450, dehumidifying operation is performed.However, when a frozen condition of the evaporator 207 is detected atstep 450, the control sequence advances to step 451. At step 451, it isjudged whether or not the room temperature is equal to or higher than apreset temperature. Then, if a condition wherein the room temperature isequal to or higher than the preset temperature is determined at step451, then this is a condition wherein no heating is required for theroom of the automobile. Accordingly, in this instance, the operation isnot changed over to heating operation. However, since a frozen conditionof the evaporator 207 has been determined at step 450, the dischargingcapacity of the evaporator 201 is lowered in order to cancel the frozencondition. Consequently, the evaporating capacity of the evaporator 207is lowered so that at least freezing at the evaporator 207 may notproceed any more. If a condition wherein the room temperature is lowerthan the preset temperature is determined at step 451, then sinceheating operation will not cause the passenger to have a disagreeablefeeling in this condition, the operation is changed over to heatingoperation. It is to be noted that it is naturally possible to eliminatethe step 451 in the control flow chart of FIG. 45. In other words, theoperation may be changed over to heating operation if freezing at theevaporator 207 is detected at step 450. Subsequently, control when afrosted condition of the outside heat exchanger 202 is detected in aheating operation condition and the operation is changed over todehumidifying operation will be described. Referring to the flow chartof FIG. 48, when a heating mode is selected at step 443, a frostedcondition of the outside heat exchanger 202 is detected at subsequentstep 452. This is because, since the outside heat exchanger 202 operatesas an evaporator in a heating operation condition as describedhereinabove, there is the possibility that frost may appear on thesurface of the outside heat exchanger 202 when the temperature of ofoutside air is low. The judgment at step 452 is performed in thefollowing conditions. First, it is judged whether or not the heatingoperation time in a condition wherein the temperature of the outsideheat exchanger 202 is lower then -3° C. has continued for more than onehour, and then it is judged whether or not the temperature of theoutside heat exchanger 202 is lower by 12° C. or more than thetemperature of outside air. When the temperature of the outside heatexchanger 202 is not lower than -3° C. this indicates that thetemperature of the surface of the outside heat exchanger 202 is not solow as will lead to frosting, and when the temperature of the outsideheat exchanger 202 is not lower by 12° C. Or more than the temperatureof outside air, this indicates that a sufficient evaporating function isassured with the outside heat exchanger 202. In other words, if frostappears on the surface of the outside heat exchanger 202, then passageof heat is obstructed, and as a result, the evaporating action of theoutside heat exchanger 202 is deteriorated. Therefore, the evaporatingpressure of refrigerant is decreased in order to maintain the functionof the refrigerating cycle. Then, refrigerant having such a decreasedevaporating pressure exhibits further decrease of the evaporatingtemperature, and as a result, the temperature of the outside heatexchanger 202 becomes lower by 12° C. or more than the temperature ofoutside air supplied to the outside heat exchanger 202. Further, thereason why it is judged whether or not the refrigerant supplying time tothe outside heat exchanger 202 has elapsed for more than one hour isthat normally it is a phenomenon which appears after continuousoperation for more than one hour that frost appears on the outside heatexchanger 202 to such a degree that it has a significant effect on theheating performance of the outside heat exchanger 202. A condition ofthe outside heat exchanger 202 is detected in this manner at step 452,and if no frost is determined, then heating operation is continued. Onthe contrary if a frosted condition is determined at step 452, then adisplay of such frosting is provided at step 452. The passenger can findthe necessity of defrosting from the frosting display. FIG. 52 shows anexample of an operation panel which includes an LED 315 for displaying afrosted condition. The operation panel further includes a defrostingswitch 314 for starting defrosting, and if the defrosting switch 314 isswitched on, then this is detected at step 453. In response to suchdetection, the operation of the automotive air conditioner is changedover to dehumidifying operation. It is to be noted that thedehumidifying operation in this instance is a refrigerating cyclewherein the outside heat exchanger 202 acts as a condenser. In otherwords, even in dehumidifying operation, a cycle wherein the outside heatexchanger 202 acts as an evaporator is excepted in the present control.It is to be noted that, with the operation panel shown in FIG. 52, notonly operation of the automotive air condition but also operation of theblower 132 are stopped simultaneously by means of a stop switch 307.When only the blower 132 is to operate, a blower switch 316 will beswitched on. Changing over of the capacity of the blower 132 upon airblasting is performed by way of the switch 301. In order to facilitatedefrosting, the compressor 201 has a great capacity. Further, theinside/outside air changing over damper 131 is changed over to an insideair mode position so that the heating capacity may not be deterioratedwhen dehumidifying operation is entered. Further, the auxiliary heaters700 and 701 are rendered operative if necessary. Besides, the blowingair amount of the blower 132 is decreased to prevent a drop of the blownout air temperature. In addition, the blower 251 for the outside heatexchanger 202 is stopped. As a result, high pressure refrigerantdischarged from the compressor 201 is supplied into the outside heatexchanger 202 so that frost adhering closely to the surface of theoutside heat exchanger 202 can be melted by heat of the refrigerant. Itis to be noted that, while, in the flow chart shown in FIG. 48,dehumidifying operation is performed when defrosting is required,alternatively dehumidifying operation having some heating effect andheating operation may be performed alternately as seen from the flowchart shown in FIG. 49. In particular, as seen at step 454 of FIG. 49,dehumidifying operation and heating operation may be performedalternately in such a manner that dehumidifying operation is performedfor a predetermined period of time, for example, for 1 to 5 minutes orso after heating operation has been performed for another predeterminedperiod of time, for example, for 30 minutes to one hour. It is to benoted that, in this instance, the condition whether or not the functionof the outside heat exchanger 202 as an evaporator has continued formore than one hour is eliminated from the conditions for detection offrosting at step 452. In other words, presence or absence of frost isjudged depending upon whether or not the temperature of the outside heatexchanger 202 is lower by more than the predetermined temperature thanthe temperature of outside air and whether or not the temperature of theoutside heat exchanger 202 is lower than -3° C. Here, the temperaturedifference between the temperature of the outside heat exchanger 202 andthe temperature of outside air is not set to 12° C. or more as at step452 of the flow chart shown in FIG. 48 but set to 8° C. or more at step452 of the flow chart shown in FIG. 49. This is because it is intendedto precautionarily detect possible or forecast frost on the outside heatexchanger 202 before the outside heat exchanger 202 is completelyfrosted. Further, in the present flow chart, in dehumidifying operationhaving some heating effect at step 454, the inside/outside air changingover damper 131 need not completely be changed over to its inside airadmitting position but may be set to another position at which both ofinside air and outside air can be admitted. Subsequently, dehumidifyingoperation having some heating effect described in the control above willbe described. In dehumidifying operation, air is first cooled in theevaporator 207 and then heated in the condenser 203, but since heat isused for sensible heat for condensing moisture in air in the evaporator207 as described hereinabove, the temperature of the air is not loweredvery much, and as a result, the temperature of air having passed both ofthe evaporator 207 and the condenser 203 rises. Further, sincedehumidifying operation involves at least three heat exchangersincluding the condenser 203, the evaporator 207 and the outside heatexchanger 202, the refrigerant condensing pressure, that is, thecondensing temperature, of the condenser 203 can be variably controlledby variably controlling the heat exchanging capacity of the outside heatexchanger 202. For example, when both of the condenser 203 and theoutside heat exchanger 202 perform a condensing action in such arefrigerating cycle as shown in FIG. 21, the condensing capacity as arefrigerating cycle can be varied by controlling the blower 251 for theoutside heat exchanger 202. When the blower 251 operates to blast agreat amount of air, the condensing capacity is increased, and as aresult, the condensing pressure of refrigerant is lowered. Thissignifies a drop of the condensing temperature of refrigerant and willcause a drop of the temperature of the condenser 203.

On the contrary when the blower 251 stops its operation, the heatexchanging capacity of the outside heat exchanger 202 is lowered, and asa result, the condensing capacity of the refrigerating cycle is lowered.Consequently, the condensing pressure of refrigerant is increased andthe condensing temperature of refrigerant in the condenser 203 israised. This will raise the temperature of the condenser 203, therebyachieving dehumidifying operation having some heating effect. Variousmeans for varying the condensing capacity of the outside air conditionermay be available in addition to such control of the blower 251 asdescribed above. For example, in a refrigerating cycle which employs adamper such as the refrigerating cycle shown in FIG. 14 which employsthe damper 253, the circuit of the damper 253 may be controlled so as toregulate the amount of air to be admitted into the outside heatexchanger 202 thereby to vary the heat exchanging capacity of theoutside heat exchanger 202. Further, where the outside heat exchanger202 is divided into a plurality of outside heat exchangers, the heatexchanging capacity may be controlled by controlling the effective heatexchanging area of the outside heat exchanger 202. Further, ifnecessary, coolant such as water is flowed into the outside heatexchanger, and the amount of the coolant may be controlled to controlthe heat exchanging capacity of the outside heat exchanger 202. Further,in an apparatus wherein air to be admitted into the outside heatexchanger 202 is changed over between outside air and air in the room ofthe automobile, the temperature of air to be admitted into the outsideheat exchanger 202 may be varied to control the heat exchanging capacityof the outside heat exchanger 202. Further, in such an apparatus asshown in FIG. 33 wherein refrigerant discharged, upon dehumidifyingoperation, from the compressor 201 is supplied in parallel to both ofthe condenser 203 and the outside heat exchanger 202, the flow rate ofrefrigerant to be supplied to the heat exchanger 202 may be varied byopening/closing control of the valve 294. In particular, when the valve294 is in an open condition, refrigerant flows to both of the outsideheat exchanger 202 and the condenser 203 so that a sufficient condensingaction is performed by the two heat exchangers 202 and 203. On thecontrary when the valve 294 is closed, a condensing action is performedonly in the condenser 203, and consequently, the condensing capacity islow. The capacity controls of the outside heat exchanger 202 describedabove may be used not only for dehumidifying operation having someheating effect but also for control of the an entire refrigeratingcycle. For example, when the pressure of the high pressure siderefrigerant rises abnormally during dehumidifying operation, thecapacity of the outside heat exchanger 202 may be varied in order toprotect the refrigerating cycle. FIG. 50 shows a flow chart of operationfor controlling the blower 251 for the outside heat exchanger 202 forthe object described just above. Where fleon R22 is employed asrefrigerant, when the high pressure side refrigerant pressure becomeshigher than 24.5 kg/cm² G, the blower 251 is rotated at a high speed. Onthe contrary when the high pressure side refrigerant temperature becomeslower than 22.5 kg/cm² G, the blower 251 is stopped. In an intermediateregion between them, the blower 251 is rotated at a low speed with somepredetermined hysteresis. FIG. 51 shows a control flow chart whencapacity control of the outside heat exchanger 202 is executed in orderto achieve both of protection of the refrigerating cycle and achievementof agreeability in operation. Upon dehumidifying operation, a pressureon the high pressure side of the refrigerating cycle is compared with apreset value at step 460. If the high pressure side pressure is higherthan the preset value, for example, 24.5 kg/cm² G, then the capacity ofthe blower 251 for the outside heat exchanger 202 is increased at step461. Consequently, the condensing capacity is enhanced and a rise inpressure to a high pressure in the refrigerating cycle is prevented. Incase it is determined that the high pressure side pressure is not higherthan the preset value, a room temperature is compared with a presettemperature subsequently at step 462. In case the room temperature ishigher by 1° C. or more than the preset temperature, it is determinedthat the heating capacity is not required very much any more, and theamount of air of the blower 251 is increased to increase the condensingcapacity. On the contrary, when the room temperature is lower by 1° C.or more than the preset temperature, it is determined that an increaseof the heating capacity is required, and the amount of air to be blastedfrom the blower 251 is decreased. Consequently, the condensing capacityof the outside heat exchanger 202 is decreased thereby to increase thecondensing pressure and the condensing temperature of the condenser 203.If the room temperature is within ±1° C. of the preset temperature, thecurrent condition of the blower 251 is maintained after then. FIG. 53shows a yet further automotive air conditioner according to the presentinvention. In the present automotive air conditioner, three heaters 203are arranged in series at three stages in the direction of a flow of airin the duct 100. A temperature sensing tube 204 is disposed at arefrigerant pipe on the upstream side of the subcooler 203c which ispositioned on the most upstream side in the direction of a flow of airamong the heaters 203, and the expansion valve 206 variably controls therefrigerating passage so that refrigerant may present a predeterminedtemperature at the entrance of the subcooler 203c. In the presentautomotive air conditioner, the expansion valve 206 controls therefrigerant passage so that refrigerant having passed the condenser 203bhas a subcooling degree of 2° to 3° C. When the temperature of air whichpasses the heaters 203 is low or when the flow rate of air is high,refrigerant is liable to be condensed in the heaters 203 and refrigeranthaving passed the condenser 203b may possibly have a sufficientsubcooling degree. In this instance, a drop of the temperature ofrefrigerant is detected by the temperature sensing tube 204 and fed backto the expansion valve 206, and consequently, the expansion valve 206varies the refrigerating passage in an expanding direction. As a result,the pressure of refrigerant on the heaters 203 side is dropped, and thesubcooling degree of refrigerant upon passage of the condenser 203b isdecreased. On the contrary when the flow rate of air to be admitted intothe heaters 203 is low or the like, sufficient radiation of heat cannotbe performed with the condensers 203a and 203b. As a result, even afterrefrigerant passes the condenser 203b, a sufficient subcooling degree ofrefrigerant cannot be achieved. In this condition, the temperature ofrefrigerant at the heat sensing tube 204 rises, and a signal thereof isfed back to the expansion valve 206. Consequently, the expansion valve206 varies the refrigerating passage in a narrowing direction. As aresult, the pressure of refrigerant in the heaters 203 on the downstreamside of the expansion valve 206 is raised, and refrigerant becomesliable to be condensed. In other words, it becomes liable to achievesubcooling with an equal flow rate of air. In this manner, thesubcooling degree of refrigerant at the location of the temperaturesensing tube 204 can be maintained to a predetermined value by variablycontrolling the passage of refrigerant by means of the expansion valve206 in response to the temperature sensing tube 204. Since, in thepresent automotive air conditioner, refrigerant at the location of thetemperature sensing tube 204 has the subcooling degree of 2° to 3° C. asdescribed above, the subcooler 203c located on the downstream side ofthe temperature sensing tube 204 in a flow of refrigerant can provide asubcooling degree of refrigerant with certainty. In particular, sincethe subcooler 203c admits on the entrance side thereof refrigerant whichalready has a predetermined (2° to 3° C.) subcooling degree, refrigerantafter passing the subcooler 203c has a higher subcooling degree. Whilethe width of the subcooling degree is not fixed depending upon thetemperature and/or the flow rate of air admitted into the subcooler203c, the subcooling degree can be increased with certainty. To increasethe subcooling degree leads to an increase of the enthalpy ofrefrigerant on the heat radiation side and hence to enhancement of theoperation efficiency of the refrigerating cycle. Particularly in thepresent automotive air conditioner, since the subcooler 203c is disposedon the downstream side of the location of the temperature sensing tube204, improvement in operation efficiency of the refrigerating cycle canbe achieved with certainty by subcooling by the subcooler 203c.Particularly where the subcooler 203c is used together with the airmixing damper 154 as in an automotive air conditioner, the flow rate ofair flowing into the heaters 203 side varies to a great extent inresponse to the opening of the air mixing damper 154. Further, thetemperature of air flowing into the heater 204 is different to a greatextent between that when refrigerant flows through the evaporator 207and that when refrigerant flows along the bypass passageway 230bypassing the evaporator 207. In this manner, in an automotive airconditioner, since the flow rate and the temperature of air flowing intothe heaters 203 vary to a great extent, in order to assure a subcoolingdegree in any operating condition, preferably the subcooler 203c isdisposed on the downstream side of the temperature sensing tube 204 asin the present automotive air conditioner. Further, in the automotiveair conditioner of FIG. 53, a shutter 255 for limiting admission of airis provided forwardly of the outside heat exchanger 202. The shutter 255corresponds to the function of the damper 253 in the automotive airconditioner shown in FIG. 4, and the occupying area can be reduced byprovision of the shutter 255 shown in FIG. 53 in place of the damper253. Further, the automotive air conditioner shown in FIG. 53 includes,similarly to the automotive air conditioner shown in FIG. 53, a fan 251for electrically controlling air to be admitted into the outside heatexchanger 202. The shutter 255 described above is particularly effectiveupon defrosting operation of the refrigerating cycle. The defrostingoperation is operation wherein refrigerant in a high temperature, highpressure condition is admitted, when frost on the outside heat exchanger202 is detected during heating operation, into the outside heatexchanger 202 to raise the temperature of the outside heat exchanger 202to melt the frost frozen on the outside heat exchanger 202. Sincedefrosting operation is performed during heating operation wherein thetemperature of outside air is low in this manner, if a large amount ofoutside air is admitted into the outside heat exchanger duringdefrosting operation, then much time is required for such defrosting anddefrosting may sometimes be impossible. Particularly with an automotiveheat exchanger, since the outside heat exchanger 202 is disposed at aposition at which it likely meets with a driving wind of the vehicle, itwill have a significant influence upon defrosting operation that theoutside heat exchanger 202 is cooled by a driving wind during running ofthe automobile. Thus, with the present automotive air conditioner, upondefrosting operation, the shutter 255 is closed to prevent a drivingwind from being admitted into the outside heat exchanger 202, and alsooperation of the fan 251 for the outside heat exchanger 202 is stopped.Subsequently, a controlling method for the refrigerating cycle shown inFIG. 53 will be described. Judgment whether the refrigerating cycleshould operate in heating operation, dehumidifying heating operation,dehumidifying operation, cooling operation or defrosting operation forthe outside heat exchanger is made in accordance with a flow ofoperations similar to that of the control shown in FIG. 48. The four-wayvalve 213, solenoid valve 231 and shutter 255 are opened and closed inthe individual modes in such a manner as seen from FIG. 54. 213 ischanged over, similarly as in the automotive air conditioners describedhereinabove, between a position (cooler condition) in which refrigerantdischarged from the compressor 201 flows to the outside heat exchanger202 side and returning refrigerant from the evaporator 207 side issucked into the compressor 201 and another position (heater condition)in which refrigerant discharged from the compressor 201 flows to theheaters 203 side and returning refrigerant is sucked from the outsideheat exchanger 202 into the compressor 201. Meanwhile, the solenoidvalve 231 opens or closes the bypass passageway 230 for flowingrefrigerant bypassing the evaporator 207 therethrough. Accordingly, whenthe solenoid valve 231 is open, refrigerant flows through the bypasspassageway 230 and does not substantially flow to the evaporator 207side. On the contrary, when the solenoid valve 231 is in a closedcondition, refrigerant flows to the evaporator 207 side. As seen fromthe control illustrated in FIG. 54, upon heating operation and upondehumidifying heating operation, the four-way valve 213 is changed overto the heater condition, in which refrigerant in a high temperature,high pressure condition is supplied to the heaters 203. On the otherhand, upon dehumidifying operation, upon cooling operation and upondefrosting operation, the four-way valve 213 is changed over to thecooler condition wherein refrigerant in a high temperature, highpressure condition is supplied to the outside heat exchanger 202. Thesolenoid valve 231 is opened only upon heating operation but is closedin any other mode. In particular, only upon heating operation,refrigerant flows bypassing the evaporator 207. As a result, uponheating operation, the evaporator 207 does not function, and air flowingin the duct 100 is not cooled by the evaporator 207 at all. In any otheroperation condition, refrigerant is supplied into the evaporator 207after passing the capillary tube 211, and the evaporator 207 functionsas a cooler for air. The shutter 255 is closed only upon defrosting ofthe outside heat exchanger 202 as described above but is open in anyother operation condition. In a heating condition A and a dehumidifyingheating condition B of FIG. 54, such control as illustrated in FIG. 55is executed. In particular, referring to FIG. 55, in a heating operationcondition, the fan 251 for the outside heat exchanger 202 is rotated atits maximum speed at step 470. Consequently, when the heat pump isoperated, absorption of heat from outside air is maximized. Inparticular, upon heating operation, refrigerant discharged from thecompressor 201 flows through the four-way valve 213 into the heaters203, in which it is condensed and liquefied, whereafter it flows throughthe expansion valve 206 and the bypass passageway 230 into the outsideheat exchanger 203. Thus, the outside heat exchanger 202 acts as anevaporator to evaporate the refrigerant, and after then, the refrigerantis fed back to the compressor 201 by way of the four-way valve 203.Accordingly, since, upon heating operation, refrigerant is evaporated inthe outside heat exchanger 202 to absorb heat from outside air, also theoutside heat exchanger 201 to maximize the amount of heat to be absorbedis rotated at its maximum speed. The speed of rotation of the compressor201 is determined from a result of comparison between an aimed blown outair temperature TAO and a blown out air temperature TA. The blown outair temperature TA is determined in accordance with a signal from theblown out air temperature sensor 323. The blown out air temperaturesensor 232 is disposed at a position at which a warm wind having passedthe heaters 203 and a cool wind having bypassed the heaters 203 aremixed with each other. When the aimed blown out air temperature ishigher than the actual blown out air temperature, this condition isdetermined at step 471, and the frequency of the invertor is increasedat step 472. On the contrary when the actual blown out air temperatureTA is higher than the aimed blown out air temperature TAO, the frequencyof the invertor is decreased at step 473. The air mixing damper 154 ispositioned at step 474 such that the entire amount of air is not flownto the heaters 203 side in order to prevent a cool wind from being blownout into the room of the automobile upon heating operation and also upondehumidifying heating operation described below. Subsequently, controlof dehumidifying heating operation B of FIG. 54 will be described. Indehumidifying heating operation, the solenoid valve 231 is closed sothat refrigerant flows to the evaporator 207 side. In particular, inthis condition, the heater 204 acts as a condenser while both of theevaporator 207 and the outside heat exchanger 202 operate asevaporators. It is judged at step 475 whether or not the temperature ofair having passed the evaporator 207 is equal to or lower than 3° C. Itis to be noted that the air temperature is judged in accordance with asignal from a temperature sensor 361 disposed on the downstream side ofthe evaporator 207. When the air temperature is higher than 3° C., theheat exchanging capacity of the outside heat exchanger 202 is loweredand the fan 251 for the outside heat exchanger 202 is stopped in orderto lower the evaporating pressures in the evaporator 207 and the outsideheat exchanger 202 at step 276. In any other condition, the speed ofrotation of the fan 251 for the outside heat exchanger 202 is controlledin accordance with a result of comparison between the aimed blown outair temperature and the actual blown out air temperature. In case theaimed blown out air temperature is higher than the actual blown out airtemperature TA, this condition is detected at step 477, and the speed ofrotation of the fan 251 for the outside heat exchanger 202 is raised atstep 478. Consequently, the amount of heat to be absorbed in the outsideheat exchanger 202 is increased to raise the blown out air temperature.On the contrary, when the actual blown out air temperature TA is higherthan the aimed blown out air temperature TAO, the speed of rotation ofthe fan 251 is lowered so as to lower the amount of heat to be absorbedin the outside heat exchanger 202. While rotation of the fan 251 for theoutside heat exchanger 202 is controlled in response to the aimed blownout air temperature TAO in this manner, when the rotation is in anintermediate region or is advancing from a maximum or minimum region tothe intermediate region, this condition is detected at step 480, and theair mixing damper 154 is opened to its maximum opening at step 474. Inany other condition, the control sequence advances to step 471 tocontrol rotation of the invertor for the compressor 201. In particular,in the control illustrated in FIG. 55, control of the capacity of therefrigerating cycle upon dehumidifying heating is first executed by thefan 251 for the outside heat exchanger 202, and only after rotation ofthe fan 251 for the outside heat exchanger 202 becomes equal to itsmaximum or minimum, control of the discharging capacity of thecompressor 201 by the invertor is executed. Subsequently, dehumidifyingoperation C shown in FIG. 54 will be described. In such dehumidifyingoperation, the four-way valve 213 is changed over so that the outsideheat exchanger 202 and the heaters 203 act as condensers and evaporationof refrigerant is performed in the evaporator 207. Also upondehumidifying operation, it is judged at step 475 whether or not thetemperature of outside air is equal to or lower than 3° C., and in casethe outside air temperature is equal to or lower than 3° C., the fan 251for the outside heat exchanger 202 is stopped at step 476. Further, inthis instance, the circuit of the air mixing damper 154 is changed overat step 481 to a condition wherein the entire amount of air flows to theheaters 203 side. Temperature control of the refrigerating cycle whenthe outside air temperature is higher than 3° C. is performed first bythe air mixing damper 154 and then by the fan 251 for the outside heatexchanger 251 and finally by capacity control of the compressor 201. Thecapacity controls of the outside heat exchanger and the compressor aresimilar to those in a dehumidifying heating operation conditiondescribed hereinabove. In the control by the air mixing damper 154,before it is detected at step 482 whether or not the air mixing damper154 is at its maximum heating position, the aimed blown out airtemperature TAO and the actual blown out air temperature TA are comparedwith each other at step 483 and then the opening of the air mixingdamper 154 is regulated at step 484 or 485. Subsequently, coolingoperation D in FIG. 54 will be described with reference to FIG. 57. Uponcooling operation, refrigerant first flows into the outside heatexchanger 202 and is then decompressed and expanded in the expansionvalve 206 after passing the heaters 203, whereafter it flows into theevaporator 207. The refrigerant is thus evaporated in the evaporator 207and then returns to the compressor 207 by way of the accumulator 212.Upon such heating operation, since air is not heated by the heaters 203,the air mixing damper 154 is displaced at step 486 to a position atwhich it closes the heaters 203. Meanwhile, since the outside heatexchanger 202 operates as a condenser, rotation of the fan 251 for theoutside heat exchanger 202 is raised to its maximum in order to maximizethe heat radiating capacity of the condenser 202 at step 487. In thiscondition, control of the cooling capacity is performed by varying thedischarging capacity of the compressor 201 at steps 471 and 272 or 473.Subsequently, defrosting operation E in FIG. 54 will be described withreference to FIG. 58. In defrosting operation, a flow of refrigerant isbasically similar to that in cooling operation, and refrigerant in ahigh temperature, high pressure condition flows into the outside heatexchanger 202. However, in order to quicken defrosting, the shutter 255is closed as described hereinabove. Further, since this condition isbasically a condition wherein heating is required, the air mixing damper154 is displaced at step 488 to a position at which the entire amount ofair flows to the heaters 203 side. Further, the fan 251 for the outsideheat exchanger 202 is stopped or kept inoperative at step 489 so that acool wind may not come to the outside heat exchanger 202. Further, inorder to complete defrosting in a short interval of time, the invertoris controlled to maximize the discharging capacity of the compressor 201at step 490. Operating conditions of the four-way valve 213, thesolenoid valve 231, the shutter 255, the air mixing damper 154, the fan251 for the outside heat exchanger 202 and the invertor for controllingthe discharging amount of the compressor 201 in the various operationconditions described above are listed up in the table shown in FIG. 59.

Further, directions of flows of refrigerant in the heating operationcondition, the dehumidifying heating operation condition, the heatingoperation condition and the defrosting operation condition describedabove are shown in FIGS. 60 to 63, respectively. A flow of refrigerantis indicated by a thick line in each of FIGS. 60 to 63. In the heatingoperation condition shown in FIG. 60, the heaters 203 operate ascondensers and a subcooler; the outside heat exchanger 202 operates asan evaporator; and the evaporator 207 disposed in the duct 100 does notoperate. This is intended to prevent cooling of air in the duct 100 uponheating by keeping the evaporator 207 inoperative. However, when theheating load is particularly high such as upon warming up immediatelyafter starting of heating, the refrigerating cycle is set similarly asin dehumidifying heating operation shown in FIG. 61 such thatrefrigerant flows also to the evaporator 207 so that the evaporator 207may operate as a heat sink. This arises from the facts that, since thetemperature of air sucked is low when the heating load is high in thismanner, a drop of the temperature of air by the evaporator 207 does notmatter very much, that absorption of heat at the evaporator 207 iscancelled by a variation of visible heat of air and the temperature ofair itself does not drop very much, and that, since absorption of heatin the entire refrigerating cycle is performed in both of the evaporator207 and the outside heat exchanger 202, the amount of absorbed heat isincreased and as a result the amount of heat radiation from the heaters203 is increased.

In particular, while heat of air sucked into the evaporator 207 isabsorbed in the evaporator 207, heat absorption then is performed firstby condensation of water in air, and consequently, the temperature ofthe air is not lowered very much even after it passes the evaporator207. Rather, a rise of the amount of heat radiation of the heaters 203acts effectively upon a rise of the temperature.

In particular, the amount of heat radiation of the heaters 203 resultsimmediately in a rise of the temperature of air passing the heaters 203,and there is no variation in latent heat. Besides, since absorption ofheat is performed in both of the evaporator 207 and the outside heatexchanger 202, the amount of heat absorption is increased and as aresult, the evaporating pressure of refrigerant is raised. As theevaporating pressure rises, the specific volume of refrigerant suckedinto the compressor 201 is decreased, and consequently, the flow rate byweight of recirculating refrigerant by the compressor is increased. Inthis manner, also the amount of heat of refrigerant supplied to theheaters 203 is increased and the amount of heat radiation by the heaters203 is increased. However, since the operation condition requires higherpower for the compressor 201, such a flow of refrigerant as shown inFIG. 60 is taken in normal heating operation as described hereinabove.FIG. 64 shows an example of a controlling operation panel for the cycleof the automotive air conditioner shown in FIG. 53. Since the automotiveair conditioner shown in FIG. 53 has a dehumidifying heating operationmode as described hereinabove, a switch for dehumidifying heating isadditionally provided comparing with the panel shown in FIG. 52.

A yet further automotive air conditioner according to the presentinvention will be described with reference to FIG. 65. The automotiveair conditioner shown in FIG. 65 eliminates the evaporating pressureregulating valve 208 comparing with the automotive air conditioner shownin FIG. 53. Prior to description of control of the automotive airconditioner shown in FIG. 65, a function of the evaporating pressureregulating valve 208 will be described first with reference to FIG. 53.

The evaporating pressure regulating valve 208 is provided to preventfrosting on the surface of the evaporator 207 when, particularly upondehumidifying heating operation, both of the evaporator 207 and theoutside heat exchanger 202 serve as heat sinks to effect evaporation ofrefrigerant. In particular, since there is the possibility that frostmay adhere to the surface of the evaporator 207 when the evaporatingpressure of refrigerant in the evaporator 207 is excessively lowereduntil the refrigerant evaporation temperature becomes lower than thefreezing point, the pressure of refrigerant at the exit of theevaporator 207 is kept higher than a predetermined value by means of theevaporating pressure regulating valve 208 in order to prevent suchpossible frosting.

In the automotive air conditioner shown in FIG. 65, the function of theevaporating pressure regulating valve 208 is achieved by opening/closingmovement of the bypass passageway 230. In particular, also in thepresent automotive air conditioner, both of the evaporator 207 and theoutside heat exchanger 202 operate, upon dehumidifying heatingoperation, as heat sinks to effect evaporation of refrigerant similarlyas in the automotive air conditioner described hereinabove withreference to FIG. 53.

In this instance, when the pressure of refrigerant in the evaporator 207is lowered below a predetermined value, this condition is detected bymeans of a temperature sensor 329 disposed on a refrigerant pipe on theexit side of the evaporator 207 and the solenoid valve 231 is opened.Since the communication resistance to refrigerant is lower in the bypasspassageway 230 than in the evaporator 207, when the solenoid valve 231is opened, refrigerant flows to the bypass passageway 230 whileadmission thereof into the evaporator 207 side is limited.

Due to the limit in supply amount of refrigerant, evaporation ofrefrigerant does not occur in the evaporator 207, and as a result, thecooling capacity of the evaporator 207 is decreased remarkably. In themeantime, since the temperature of air admitted into the evaporator 207is equal to a room temperature, if operation is continued in thecondition wherein the cooling capacity is decreased remarkably, thenfrost appearing on the surface of the evaporator 207 will be melted. Inthis manner, the evaporation temperature of refrigerant in theevaporator 207 can be restricted within a predetermined width bycontrolling opening/closing movement of the solenoid valve 231 inresponse to a temperature of refrigerant on the exit side of theevaporator 207 in this manner, and as a result, a function similar tothat of the evaporating pressure regulating valve described hereinabovecan be achieved. A yet further automotive air conditioner according tothe present invention will be described with reference to FIG. 66.

While, in the automotive air conditioner shown in FIG. 53, the bypasspassageway is provided sidewardly of the heaters 203 and, upon cooling,the air mixing damper 154 closes the heaters 203 so that air may flowalong the bypass passageway, the heaters 203 in the automotive airconditioner shown in FIG. 66 is disposed over the entire area in theduct 100. Then, upon heating, a bypass passageway 234 is opened so thatrefrigerant may not flow to the heaters 203. The bypass passageway 234is provided to communicate a refrigerant pipe on the entrance side andanother refrigerant pipe on the exit side of the heaters 203 with eachother, and a solenoid valve 232 for opening or closing the bypasspassageway 234 is disposed intermediately of the bypass passageway 234.

Accordingly, upon heating operation, the solenoid valve 232 is opened toopen the bypass passageway 234. Simultaneously, another solenoid valve233 provided in the entrance side refrigerant pipe is closed so thatrefrigerant may not flow to the heaters 203. Accordingly, upon cooling,refrigerant is not supplied to the heaters 203, and refrigerantaccumulated in the heaters 203 will have a high subcooling degree. Sincethe expansion valve 206 is controlled so that refrigerant on theentrance side of the subcooler 203c may have a predetermined subcoolingdegree as described hereinabove, in a condition wherein refrigerant isnot supplied any more and has a predetermined subcooling degree in thismanner, such signal is inputted to the expansion valve 206 andconsequently, the expansion valve 206 is opened until its opening areapresents its maximum in order to maximize the flow rate of refrigerant.

Accordingly, suitable cooling operation cannot be performed in thiscondition. However, in the present automotive air conditioner, since thecapillary tube 211 is provided in series to the expansion valve 206,refrigerant is decompressed and expanded suitably by the capillary tube211 even in such a condition as described just above. Subsequently, ayet further automotive air conditioner according to the presentinvention will be described with reference to FIG. 67.

The automotive air conditioner shown in FIG. 67 employs a receiver 205similarly to the automotive air conditioner shown in FIG. 3. In thepresent automotive air conditioner, however, the receiver 205 isdisposed between the exit side of the condenser 203b and the entranceside of the subcooler 203c of the heaters 203. Since the receiver 205has a gas/liquid interface and only delivers liquid refrigerant, liquidrefrigerant is supplied with certainty to the subcooler 203c.Consequently, the subcooler 203c can provide a subcooling degree ofrefrigerant with certainty. As described hereinabove, when the airconditioner is used as an automotive air conditioner, the variation inamount of air admitted into the heaters 203 when the air mixing damper154 is opened and closed and the variation in temperature of air whenthe evaporator 207 operates and does not operate are great, but wherethe subcooler 203c is disposed on the downstream of the receiver 205 asin the present automotive air conditioner, a sufficient subcoolingdegree can be obtained with certainty in any operation condition.Further, in the present automotive air conditioner, the expansion valve206 varies the throttling amount of the refrigerant pipe so that apredetermined dryness may be obtained for refrigerant on the suckingside of the compressor 201 sensing tube for the expansion valve 206 isdisposed between the four-valve 214 and the compressor 201, to whicheverposition the four-way valve 214 is changed over, a temperature ofsuction refrigerant returning to the compressor 201 can always bedetected.

It is to be noted that, in the automotive air conditioner shown in FIG.67, the auxiliary heater 700 is disposed on the downstream side of theheaters 203 in a flow of air in order to complement the heating capacityupon heating or upon dehumidifying heating. A yet further automotive airconditioner according to the present invention will be describedsubsequently with reference to FIG. 68. The automotive air conditionershown in FIG. 68 solves a disadvantage when an evaporating pressureregulating valve of the fully closed type is employed as the evaporatingpressure regulating valve 208. When the evaporating pressure regulatingvalve 208 is of the fully closed type, if cold air flows into theevaporator 207 as upon, for example, starting at a low temperature, thetemperature of refrigerant on the exit side of the evaporator 207 islowered below a predetermined value and consequently the evaporatingpressure regulating valve 208 will close the refrigerant pipe.

If the refrigerant pipe is closed in this manner, refrigerant will notreturn to the compressor 201, and consequently, such a disadvantage asseizure of the compressor 201 may take place. Therefore, in an operationcondition wherein the evaporation pressure regulating valve 208 closesthe refrigerant passage in this manner, the solenoid valve 231 is openedtemporarily so that refrigerant may flow to the downstream side of theevaporating pressure regulating valve 208 by way of the bypasspassageway 230 bypassing the evaporating pressure regulating valve 208.While, in this condition, the evaporator 207 does not functiontemporarily, if air to be sucked into the duct 100 is changed over toinside air and the temperature of air passing the duct 100 rises, thenalso the temperature of refrigerant in the evaporator 207 rises, andconsequently, the evaporating pressure regulating valve 208 will openthe refrigerant passage.

Accordingly, after then, the bypass passageway 230 can be closed to flowrefrigerant to the evaporator 207 side. Accordingly, in the presentautomotive air conditioner, the bypass passageway 230 is only requiredto bypass the evaporating pressure regulating valve 208 and need notnecessarily bypass the evaporator 207. Further, if the evaporatingpressure regulating valve 208 is of the type which can pass apredetermined amount of refrigerant even when it assumes its minimumthrottling condition, the bypass passageway 230 need not necessarily beprovided. Subsequently, a yet further automatic air conditioneraccording to the present invention will be described with reference toFIG. 69.

The automotive air conditioner shown in FIG. 69 can achieve defrostingof the outside heat exchanger 202 during heating operation and duringdehumidifying heating operation without considerable deterioration ofthe dehumidifying heating function. To this end, in the automatic airconditioner shown in FIG. 69, the three-way valves 275, 276 and 277 arechanged over to change over a sequence of a flow of refrigerant. Inparticular, in any of heating operation and dehumidifying heatingoperation in which defrosting is involved, refrigerant in a hightemperature, high pressure condition is supplied from the compressor 201into the heater 203, which thus operates as a heat radiator. Further,refrigerant in a low temperature, low pressure condition is supplied toboth of the evaporator 207 and the outside heat exchanger 202, whichboth operate thus as heat sinks.

However, in heating operation and in dehumidifying heating operation inwhich defrosting is involved, refrigerant flows in different ordersthrough the evaporator 207 and the outside heat exchanger 202. Upondehumidifying heating operation, refrigerant condensed by the heater 203flows, after passing the expanding means 206, first into the evaporator207 and then into the outside heat exchanger 202. This is intended,because it is normally forecast that the temperature of outside air islow upon dehumidifying heating operation, to assure operation of theautomotive air conditioner even in such condition. In particular, whenthe outside air temperature is, for example, lower than 0° C., theevaporating temperature of refrigerant is lower than the freezing pointand lower than the outside air temperature so that refrigerant may beevaporated in the outside heat exchanger 202 in such outside airtemperature condition.

Here, if the evaporator 207 is disposed on the downstream side of theoutside heat exchanger 202 in a flow of refrigerant, then theevaporating temperature of refrigerant in the evaporator 207 will belower than the evaporating temperature of refrigerant in the outsideheat exchanger 202 and lower than the freezing point. Consequently,frosting takes place on the surface of the evaporator 207 and theventilation resistance in the duct 100 is increased.

As a result, good dehumidifying heating operation cannot be achieved. Onthe other hand, if the evaporator 207 is disposed on the upstream sideof the outside heat exchanger 202 in a flow of refrigerant, then theevaporating temperature of refrigerant in the evaporator 207 can be madehigher than the evaporating temperature of refrigerant in the outsideheat exchanger 202. Consequently, the refrigerant temperature ofrefrigerant in the evaporator 207 can always be held to a predeterminedtemperature of 2° to 3° C. In this instance, frosting of the outsideheat exchanger 202 seems to matter. However, since the disadvantage byfrosting is more serious with the evaporator 207 than with the outsideheat exchanger 202, the evaporator 207 is disposed on the upstream sidein a flow of refrigerant upon normal dehumidifying heating operation.Then, in case frosting of the outside heat exchanger 202 becomesparticularly significant in such operation condition, the flow ofrefrigerant is changed over so that refrigerant having passed the heater203 first flows into the outside heat exchanger 202.

Consequently, refrigerant in a high temperature, high pressure conditionis supplied into the outside heat exchanger 202 to raise the temperatureof the surface of the outside heat exchanger 202. As a result, frostappearing on the surface of the outside heat exchanger 202 is melted. Inthis operation condition, operation of the fan 251 for the outside heatexchanger 202 is stopped in order to accelerate defrosting. Then, therefrigerant having passed the outside heat exchanger 202 is decompressedand expanded in the capillary tube 211 and then flows into theevaporator 207. Further, as described hereinabove, preferably an insideair mode is entered to set the amount of a wind of the inside blower tothe Lo position.

FIGS. 70 to 73 show flows of refrigerant in the automatic airconditioner shown in FIG. 69. In particular, FIG. 70 shows a heatingoperation condition and FIG. 71 shows a cooling operation condition.Further, FIG. 72 shows a dehumidifying heating operation condition, andFIG. 73 shows a condition wherein defrosting of the outside heatexchanger 202 is performed. In all of FIGS. 70 and 73, only a pipe inwhich refrigerant flows is indicated with a thick line. Subsequently, ayet further automotive air conditioner according to the presentinvention will be described with reference to FIG. 74. The refrigeratingcycle shown in FIG. 74 is an accumulator cycle which additionallyincludes, comparing with the cycle shown in FIG. 21, a passageway 297bypassing the capillary tube 211 and a solenoid valve 294 for opening orclosing the passageway 294. Refrigerant flow passage changing over meanschanges over flowing directions of refrigerant upon cooling operation,upon heating operation, upon dehumidifying operation, and upondefrosting operation during dehumidifying operation (hereinafterreferred to as defrosting operation). Similarly as in the automotive airconditioner described hereinabove, the refrigerant flow passage changingover means includes a four-way valve 213 for changing over thedischarging direction of the refrigerant compressor 201 between thatupon cooling operation and that upon any other operation, a firstsolenoid opening/closing valve 201 for bypassing, upon heatingoperation, the first decompressing apparatus 211 and the evaporator 207on the upstream side, a second solenoid opening/closing valve 260 forbypassing, upon dehumidifying operation, the second decompressingapparatus 266, and a third solenoid opening/closing valve 298 forbypassing, upon defrosting operation, the first decompressing apparatus211.

A pair of check valves 262 and 265 for controlling flowing directions ofrefrigerant are also provided. The flow passage changing over meanschanges over a flow of refrigerant in the following manner upon coolingoperation, upon heating operation, upon dehumidifying operation and upondefrosting operation. Upon cooling operation, refrigerant dischargedfrom the refrigerant compressor 201 flows in the order of four-way valve213--outside heat exchanger 202--first decompressing apparatus211--evaporator 207--accumulator 212--refrigerant compressor 201 (referto arrow marks C in FIG. 74). discharged from the refrigerant compressor201 flows in the order of four-way valve 213--heater 203--seconddecompressing apparatus 266--outside heat exchanger 202--first solenoidopening/closing valve 261--accumulator 212--refrigerant compressor 201(refer to arrow marks H in FIG. 74).

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 flows in the order of four-way valve213--heater 203--second solenoid opening/closing valve 260--outside heatexchanger 202 (the outside blower 251 is inoperative then)--firstdecompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 201 (refer to arrow marks D in FIG. 74).Upon defrosting operation wherein defrosting of the evaporator 207 isperformed in a dehumidifying operation condition, refrigerant dischargedfrom the refrigerant compressor 201 flows in the order of four-way valve213--heater 203--second decompressing apparatus 266--outside heatexchanger 202 (the outside blower 251 is operative then) --thirdsolenoid opening/closing valve 298--evaporator 207 --accumulator212--refrigerant compressor 201 (refer to arrow marks F in FIG. 74).

The controlling apparatus 300 includes a temperature sensor fordetecting a temperature of a fin or a tube of the evaporator 207 or atemperature of air having passed the evaporator 207. The temperaturesensor is provided to detect frost on the evaporator 207, and when thetemperature of the fin of the evaporator 207 detected by the temperaturesensor is lowered to 0° C., the controlling apparatus 300 forecastsfrosting and executes defrosting of the evaporator 207 in order toprevent frosting.

Subsequently, defrosting operation during dehumidifying operation of theautomotive air conditioner shown in FIG. 74 will be described. If thetemperature detected by the temperature sensor during dehumidifyingoperation becomes lower than 0° C., then the controlling apparatus 300closes the second solenoid opening/closing valve 260, opens the thirdsolenoid opening/closing valve 298 and renders the outside blower 251operative to effect defrosting operation. Then, if the temperaturedetected by the temperature sensor rises higher than 1° C., then thecontrolling apparatus 300 opens the second solenoid opening/closingvalve 260, closes the third solenoid opening/closing valve 298 andrenders the outside blower 251 inoperative to return the operation todehumidifying operation. If dehumidification is set by means of the airconditioning mode setting switch 314 of the operation panel by thepassenger, then outside air or inside air selected by the inside/outsideair changing over means 131 is sucked into the duct 100 by the blower132, passes through the evaporator 207, the heater 203 and the auxiliaryheaters 700 and 701 and is blown out into the room of the automobilefrom a spit hole set by the blowing mode changing over switch 303. Theamount of a wind then is set by means of the wind amount setting switch301. In the refrigerating cycle upon dehumidifying operation,refrigerant in a high temperature, high pressure condition dischargedfrom the refrigerant compressor 201 is introduced into the heater 203 bymeans of the four-way valve 213. Here, the refrigerant exchanges heatwith air flowing in the duct 100 to heat the air in the duct 100 whileit is condensed and liquefied in the heater 203. The thus liquefiedrefrigerant then flows into the outside heat exchanger 202 by way of thesecond solenoid opening/closing valve 260. In this instance, since theoutside blower 251 is inoperative, the liquefied refrigerant passesthrough the outside heat exchanger 202 and is then decompressed andexpanded into low temperature, low pressure mist in the firstdecompressing apparatus 211. The refrigerant in the form of mist flowsinto the evaporator 207, in which it takes heat away from air flowing inthe duct 100 so that it is evaporated. Then, the thus evaporatedrefrigerant is resucked into the refrigerant compressor 210 by way ofthe accumulator 212. Air sucked into the duct 100 is lowered intemperature when it passes the evaporator 203, and consequently,saturated vapor in the air is condensed and adheres to the evaporator207. After then, the air is heated when it passes the heater 203, andconsequently, the moisture in the air decreases remarkably. As a result,good dehumidifying operation is performed. If the temperature of airsucked into the duct 100 during dehumidifying operation becomes so lowthat the temperature of the evaporator 207 detected by the temperaturesensor is lower than 0° C., then the controlling apparatus 300 controlsthe flow passage changing over means to change over the refrigerant flowpassage of the refrigerating cycle to that for dehumidifying operation.In short, the second solenoid opening/closing valve 260 is closed whilethe third solenoid opening/closing valve 298 is opened. Consequently,refrigerant condensed and liquefied in the heater 203 is decompressedand expanded into low temperature, low pressure mist in the firstdecompressing apparatus 266, and then flows into the outside heatexchanger 202. In this instance, since the outside blower 251 isoperating, the outside heat exchanger 202 functions as a refrigerantevaporator together with the evaporator 207. The refrigerant admittedinto the evaporator 207 by way of the outside heat exchanger 202 and thethird solenoid opening/closing valve 298 exchanges heat with outside airpassing the outside heat exchanger 202 and also with air flowing in theduct 100 and passing the evaporator 207 so that it is evaporated. Thethus evaporated refrigerant is then re-sucked into the refrigerantcompressor 201 by way of the accumulator 212. The evaporating pressureis raised by using the outside heat exchanger 202 as a refrigerantevaporator together with the evaporator 207. Consequently, while theevaporator 207 functions as a refrigerant evaporator, the temperature ofthe evaporator 207 rises and as a result, frosting of the evaporator 207can be prevented. Then, if the temperature of the fin of the evaporator207 detected by the temperature sensor becomes higher than 1° C., thenthe controlling apparatus 100 controls the flow passage changing overmeans to open the second solenoid opening/closing valve 260 and closethe third solenoid opening/closing valve 298 to change over therefrigerant flow passage of the refrigerating cycle to that fordehumidifying operation. Further, the outside blower 251 is renderedinoperative, thereby performing dehumidifying operation describedhereinabove. In the automotive air conditioner shown in FIG. 74, sincethe evaporator 207 in the duct 100 always functions, upon dehumidifyingoperation, as a refrigerant evaporator such that dehumidifying operationis maintained even in defrosting operation as described hereinabove, thetemperature in the room of the automobile can normally be kept low.Further, since defrosting can be performed without lowering the capacityof the refrigerant compressor 201, no drop in blown out air temperatureis invited upon defrosting operation. FIG. 75 is a refrigerant circuitdiagram of a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner includes athree-way valve 269 in place of the four-way valve 213 of the automotiveair conditioner shown in FIG. 74 and additionally includes a fourthsolenoid opening/closing valve 268 for returning, upon coolingoperation, refrigerant accumulated in the heater 203 to the accumulator212. FIG. 76 is a refrigerant circuit diagram of a yet furtherautomotive air conditioner according to the present invention. Thepresent automotive air conditioner includes two fifth and sixth solenoidopening/closing valves 270 and 271 in place of the three-way valve 269of the automotive air conditioner shown in FIG. 75.

FIG. 77 is a refrigerant circuit diagram of a yet further automotive airconditioner according to the present invention. The present automotiveair conditioner includes a three-way valve 272 in place of the fifthsolenoid opening valve 270 for changing over the discharging directionof the refrigerant compressor 201 in the automotive air conditionershown in FIG. 76 and the fourth solenoid opening/closing valve 268 forreturning, upon cooling operation, refrigerant accumulated in the heater203 to the accumulator 212. FIG. 78 is a refrigerant circuit diagram ofa yet further automotive air conditioner according to the presentinvention. The refrigerating cycle of the present automotive airconditioner is changed over in the following manner in accordance withvarious operation modes by flow passage changing over means. Uponcooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213--outsideheat exchanger 202 --seventh solenoid opening/closing valve 296--firstdecompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 201 (refer to arrow marks C in FIG. 78).Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213--heater203--second decompressing apparatus 266--seventh solenoidopening/closing valve 296 --outside heat exchanger 202--four-way valve213--accumulator 212--refrigerant compressor 201 (refer to arrow marks Hin FIG. 78). Upon dehumidifying operation, refrigerant discharged fromthe refrigerant compressor 201 flows in the order of the four-way valve213--heater 203--second decompressing apparatus 266--eighth solenoidopening/closing valve 298--evaporator 207--accumulator 212--refrigerantcompressor 201 (refer to arrow marks D in FIG. 78). Upon defrostingoperation, refrigerant discharged from the refrigerant compressor 201passes in the order of the four-way valve 213--heater 203--seconddecompressing apparatus 266. The refrigerant having passed the seconddecompressing apparatus 266 is divided into two flows. In one of the twoflows, the refrigerant flows in the order of the eighth solenoidopening/closing valve 298--evaporator 207--accumulator 212--refrigerantcompressor 201. Meanwhile, in the other flow, the refrigerant flows inthe order of the seventh solenoid opening/closing valve 296--outsideheat exchanger 202--four-way valve 213--accumulator 212--refrigerantcompressor 201 (refer to arrow marks F in FIG. 78).

FIG. 79 shows a refrigerant circuit diagram of a yet further automotiveair conditioner according to the present invention. The refrigeratingcycle of the present automotive air conditioner is changed over in thefollowing manner in accordance with various operation modes by flowpassage changing over means. Upon cooling operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of thefour-way valve 213--ninth solenoid opening/closing valve 295--outsideheat exchanger 202--tenth solenoid opening/closing valve 291--firstdecompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 201. Upon heating operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of thefour-way valve 213--heater 203--eleventh solenoid opening/closing valve292--second decompressing apparatus 266--outside heat exchanger202--ninth solenoid opening/closing valve 293--four-way valve213--accumulator 212--refrigerant compressor 201. Upon dehumidifyingoperation, refrigerant discharged from the refrigerant compressor 201 isdivided into two flows one of which flows to the four-way valve 213 andthe other of which flows to a twelfth solenoid opening/closing valve294. The refrigerant flowing to the four-way valve 213 flows in theorder of the four-way valve 213--heater 203--tenth solenoidopening/closing valve 291--first decompressing apparatus 211--evaporator207--accumulator 212--refrigerant compressor 201. On the other hand, therefrigerant flowing to the twelfth solenoid opening/closing valve 294flows in the order of the twelfth solenoid opening/closing valve294--outside heat exchanger 202--tenth solenoid opening/closing valve291--first decompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 212. Upon defrosting operation, refrigerantdischarged from the refrigerant compressor 201 passes in the order ofthe four-way valve 213--heater 203. The refrigerant having passed theheater 203 is divided into two flows. In one of the two flows, therefrigerant flows in the order of the tenth solenoid opening/closingvalve 291--first decompressing apparatus 211--evaporator207--accumulator 212--refrigerant compressor 201. Meanwhile, in theother flow, the refrigerant flows in the order of the eleventh solenoidopening/closing valve 292--second decompressing apparatus 266--outsideheat exchanger 202--ninth solenoid opening/closing valve 293--four-wayvalve 213--accumulator 212--refrigerant compressor 201. FIG. 80 is arefrigerant circuit diagram of a yet further automotive air conditioneraccording to the present invention. The present automotive airconditioner adopts the construction wherein refrigerant always flows inthe evaporator 207. Thus, a bypass wind passageway for flowing airbypassing the evaporator 207 is provided in the duct 100, and uponheating operation, the evaporator 207 is closed by the damper 159 on theupstream side so that refrigerant may not exchange heat with air in theduct 100. The refrigerating cycle of the present automotive airconditioner is changed over in the following manner in accordance withvarious operation modes by flow passage changing over means. Uponcooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213--outsideheat exchanger 202--first decompressing apparatus 211--evaporator207--accumulator 212--refrigerant compressor 201. Upon heatingoperation, refrigerant discharged from the refrigerant compressor 201flows in the order of the four-way valve 213--heater 203--seconddecompressing apparatus 266--outside heat exchanger 202--solenoidopening/closing valve 298--evaporator 207 --accumulator 212--refrigerantcompressor 201. Upon dehumidifying operation, refrigerant dischargedfrom the refrigerant compressor 201 flows in the order of the four-wayvalve 213--heater 203--solenoid opening/closing valve 260--outside heatexchanger 201--first decompressing apparatus 211--evaporator207--accumulator 212--refrigerant compressor 201. Upon defrostingoperation, refrigerant discharged from the refrigerant compressor 201flows in the order of the four-way valve 213--heater 203--seconddecompressing apparatus 266--outside heat exchanger 202--solenoidopening/closing valve 298--evaporator 207 --accumulator 212--refrigerantcompressor 201 is a refrigerant circuit diagram of a yet furtherautomotive air conditioner according to the present invention. Thepresent automotive air conditioner adopts the construction whereinrefrigerant always flows in the evaporator 207. Thus, a bypass windpassageway for flowing air bypassing the heater 203 is provided in theduct 100, and upon cooling operation, the heater 203 is closed by thedamper 154 on the downstream side so that refrigerant and air in theduct 100 may not exchange heat in the heater 203. The refrigeratingcycle of the present automotive air conditioner is changed over in thefollowing manner in accordance with various operation modes by flowpassage changing over means. Upon cooling operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of theheater 203--solenoid opening/closing valve 260--outside heat exchanger202--first decompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 201. Upon heating operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of theheater 203--second decompressing apparatus 266--outside heat exchanger202--solenoid opening/closing valve 261--accumulator 212--refrigerantcompressor 201. Upon dehumidifying operation, refrigerant dischargedfrom the refrigerant compressor 201 flows in the order of the heater203--solenoid opening/closing valve 260--outside heat exchanger202--first decompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 201. Upon defrosting operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of theheater 203--second decompressing apparatus 266--outside heat exchanger202--solenoid opening/closing valve 298--evaporator 207--accumulator212--refrigerant compressor 201. A yet further automotive airconditioner according to the present invention can be attained by acircuit similar to the refrigerating circuit shown in FIG. 40. Thepresent automotive air conditioner will thus be described with referenceto FIG. 40. The present automotive air conditioner adopts theconstruction wherein refrigerant always flows in the evaporator 207 andthe heater 203. Thus, a bypass wind passageway for flowing air bypassingthe evaporator 207 and another bypass wind passageway for flowing airbypassing the heater 203 are provided in the duct 100, and upon heatingoperation, the evaporator 207 is closed by the damper 159 on theupstream side, but upon cooling operation, the heater 203 is closed bythe damper 154 on the downstream side. The refrigerating cycle of thepresent automotive air conditioner is changed over in the followingmanner in accordance with various operation modes by flow passagechanging over means. Upon cooling operation, refrigerant discharged fromthe refrigerant compressor 201 flows in the order of the heater203--solenoid opening/closing valve 260--outside heat exchanger202--first decompressing apparatus 211--evaporator 207--accumulator212--refrigerant compressor 201. Upon heating operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of theheater 203--second decompressing apparatus 266--outside heat exchanger202--solenoid opening/closing valve 261--evaporator 207--accumulator212--refrigerant compressor 201. Upon dehumidifying operation,refrigerant discharged from the refrigerant compressor 201 flows in theorder of the heater 203--solenoid opening/closing valve 260--outsideheat exchanger 202--first decompressing apparatus 211--evaporator207--accumulator 212--refrigerant compressor 201. Upon defrostingoperation, refrigerant discharged from the refrigerant compressor 201flows in the order of the heater 203--second decompressing apparatus266--outside heat exchanger 202--solenoid opening/closing valve261--evaporator 207--accumulator 212--refrigerant compressor 201. A yetfurther automotive air conditioner according to the present inventioncan be attained by a circuit similar to the refrigerating circuit shownin FIG. 7. The present automotive air conditioner will thus be describedwith reference to FIG. 7. The present automotive air conditioner adoptsthe construction wherein refrigerant always flows in the evaporator 207and the heater 203. Thus, a bypass wind passageway for flowing airbypassing the heater 203 is provided in the duct 100, and the opening ofthe damper 154 on the downstream side is varied to adjust the mount ofair to pass the heater 203 and the amount of air to pass the bypasspassageway to adjust the blown out air temperature. The refrigeratingcycle of the present automotive air conditioner is changed over in thefollowing manner by flow passage changing over means which employs twofour-way valves 213 and 214. Upon cooling operation and upon defrostingoperation, refrigerant discharged from the refrigerant compressor 201flows in the order of the four-way valve 213 --outside heat exchanger202--four-way valve 214--heater 203--first decompressing apparatus211--evaporator 207--four-way valve 213--accumulator 212--refrigerantcompressor 201. Upon heating operation and upon defrosting operation,refrigerant discharged from the refrigerant compressor 201 flows in theorder of the four-way valve 213 --four-way valve 214--heater 203--firstdecompressing apparatus 211--evaporator 207--four-way valve 214--outsideheat exchanger 203--our-way valve 213--accumulator 212--refrigerantcompressor 201. Further, dehumidifying operation and defrostingoperation can be achieved even with such a construction as shown in FIG.11 wherein a bypass wind passageway is formed sidewardly of theevaporator 207. Further, dehumidifying operation and defrostingoperation can be achieved similarly even with a construction wherein thefour-way valve 214 is replaced by four check valves 216, 217, 218 and219 as shown in FIG. 13.

Further, while a temperature sensor is employed as a sensor fordetecting frost on the evaporator in the automotive air conditionersdescribed hereinabove, not a temperature but a pressure of refrigerantin the pipe on the exit side of the evaporator may alternatively bedetected to forecast frosting from an evaporating temperature ofrefrigerant. Or else, a sensor for detecting a loss in pressure of theevaporator may be used to detect frosting from a variation in loss inpressure of a wing passing the evaporator. FIGS. 82 to 85 showrefrigerating cycles of a yet further automotive air conditioneraccording to the present invention. In particular, FIGS. 82 to 85illustrate dehumidifying heating, defrosting, cooling and heatingconditions, respectively, and indicate a pipe in which refrigerant flowsby a thick line. The expansion pipe 206 employed here is a temperaturedifferential expansion valve which varies the throttling amount of therefrigerant flow passage so that refrigerant on the exit-side of theheater 203 adjacent the condenser may have a predetermined subcoolingdegree. Upon cooling operation, refrigerant discharged from therefrigerant compressor 201 flows in the order of the four-way valve213--outside heat exchanger 202--expanding means 260--evaporator207--accumulator 212--refrigerant compressor 201. Upon heating operation(FIG. 85), refrigerant flows in the order of the compressor201--four-way valve 213--heater 203--expansion valve 206--outside heatexchanger 202--accumulator 212--refrigerant compressor 201. When thereis the possibility upon heating that the windshield may be fogged,dehumidifying heating (FIG. 82) operation is performed, and in thisinstance, refrigerant flows in the order of the compressor 201--heater203--expansion valve 206--outside heat exchanger 202--solenoidopening/closing valve 266--evaporator 207--accumulator 212--refrigerantcompressor 201. In case the surface of the outside heat exchanger 202 isfrozen upon heating, the condition of the outside heat exchanger 202 isdetected and defrosting operation (FIG. 83) is started. Upon defrostingoperation, refrigerant circulates in the refrigerant cycle in the orderof the refrigerant compressor 201--heater 203--solenoid valve298--outside heat exchanger 202--expanding capillary tube260--evaporator 207--accumulator 212--compressor 201. The difference ofthe refrigerating cycles from those of the automotive air conditionershown in FIG. 63 is that, while refrigerant flows, upon defrostingoperation, in the order of the outside heat exchanger 202--heater 203 inthe automotive air conditioner shown in FIG. 63, refrigerant flows inthe reverse order of the heater 203--outside heat exchanger 202 in thepresent automotive air conditioner. When discharged refrigerant flows,upon defrosting operation, first into the heater 203 as in the presentautomotive air conditioner, a predetermined subcooling degree can alwaysbe obtained at the heater 203. This will be .described subsequently.Since, in the automotive air conditioner shown in FIG. 63, refrigerantis condensed first in the outside heat exchanger 202, when thetemperature of outside air is low at 0° C. or so, it is forecast thatrefrigerant after passing the outside heat exchanger 202 may be cooledto 10° C. or so and condensed. Here, if it is assumed that therefrigerant has a subcooling degree of 2° to 3° C. or so when it passesthe outside heat exchanger 202, the temperature corresponding to acondensing pressure of the refrigerant when it passes the outside heatexchanger 202 is 12° to 13° C. or so. On the other hand, for a whileafter the operation is changed over from heating operation to defrostingoperation, air is not cooled sufficiently in the evaporator 207 andcomparatively warm air of a temperature equal to the room temperature orso will flow into the heater 203. The air temperature is in most cases12° to 13° C. or more and may sometimes be higher than a temperaturecorresponding to the condensing pressure described above. In thisinstance, refrigerant condensed once in the outside heat exchanger 202will be evaporated again when it passes the heater 203. The refrigerantdoes not have a subcooling degree at least when it passes the condenserportion of the heater 203. As a result, the expansion valve 206 of thetemperature differential type will throttle the flow rate of refrigerantso as to obtain a subcooling degree, and consequently, the amount ofrefrigerant which circulates in the cycle will be reduced remarkably. Onthe other hand, in the automotive air conditioner shown in FIG. 85,since refrigerant discharged from the compressor 261 flows, even upondefrosting operation, similarly as upon heating operation, first intothe heater 203, such a disadvantage as described above does not occureven upon changing over from heating operation to defrosting operation.In the present automotive air conditioner, refrigerant having passed theheater 203 after defrosting is lowered in temperature, and while thetemperature of refrigerant in the outside heat exchanger 202 is lowcomparing with that of refrigerant which advances from the compressor201 directly to the outside heat exchanger 202, since refrigerant of atemperature higher than 0° C. flows any way into the outside heatexchanger 202, defrosting operation is achieved well.

Moreover, in FIG. 85 the shutter 225 is drawn in an open state, but whenperforming defrosting it is not preferable that cold air be introducedinto the outside heat exchanger 202, and the shutter 225 closes duringdefrosting operation.

After performing defrosting with the refrigeration cycle indicated inFIG. 83, when the frost of the outside heat exchanger 202 melts, areturn to the heating operation mode indicated in FIG. 85 is againeffected. At this time, however, in the defrosting operation modeindicated in FIG. 83 high-pressure, high-temperature refrigerant flowsinto the outside heat exchanger 202. Consequently, whereas condensationof refrigerant was performed by the outside heat exchanger 202, in theheating operation mode indicated in FIG. 85 the outside heat exchanger202 functions as an evaporator, and refrigerant is immediately takenfrom the outside heat exchanger, through the accumulator 212, and intothe compressor 201 side.

Consequently, when changing from the defrosting operation mode indicatedin FIG. 83 immediately to the heating operation mode indicated in FIG.85, refrigerant condensed and maintained within the outside heatexchanger 202 is taken at once through the accumulator 212 into thecompressor 201 side. Here, the accumulator 212 operates so as to absorbfluctuations in refrigerant flow, but along with the large capacity ofthe outside heat exchanger 202, in a case where a large amount ofrefrigerant has been momentarily sucked from the outside heat exchanger202, a state wherein vapor-liquid separation cannot be performedsufficiently even by accumulator 212 is hypothesized. In this case,liquid vapor which has not undergone vapor-liquid separation is takeninto the compressor 201 side, and leads to liquid compression in thecompressor 201 which is not desirable. Accordingly, when returning tothe heating operation mode indicated in FIG. 85 from the defrostingoperation mode indicated in FIG. 83, it is preferable to pass oncethrough the dehumidifying operation mode indicated in FIG. 82. That isto say, in the dehumidifying operation mode indicated in FIG. 82,because an evaporator 207 is interposed downstream of the outside heatexchanger 202 liquid refrigerant condensed within the outside heatexchanger 202 is also discharged once to the evaporator 207 side.Accordingly, if, after the amount of liquid refrigerant within theoutside heat exchanger 202 drops, the heating operation mode indicatedin FIG. 85 is enabled, the above-described problem of liquid compressiondoes not occur. Moreover, refrigerant comes to be retained within theevaporator 207 at this time, but the refrigerant within this evaporator207 comes to be moved to the foregoing accumulator 212 side by means ofsuction of the compressor 201.

Additionally, in the refrigerant circuit indicated in FIG. 83, becausethe evaporator 207 and heater 203 operate together, air passing throughthe duct 100 comes to be heated by the heater 203 after being chilled bythe evaporator 207. As a result of this, good dehumidification isperformed even in the refrigeration cycle state indicated in FIG. 83.During this dehumidifying operation the shutter 255 operates so as toopen an air path as shown in FIG. 83.

The refrigeration cycle indicated in FIG. 83 was treated as defrostingoperation in the above-described example, but control is performedsimilarly also when dehumidifying operation is performed. That is tosay, in a case wherein it is caused to change to the heating operationmode indicated in FIG. 85 after dehumidification is performed in thecycle indicated in FIG. 83, it is preferable not to switch abruptly toheating operation, but rather to effect heating operation after onceperforming the dehumidifying operation mode indicated in FIG. 82.

FIG. 103 is a flowchart indicating the above-described control. In step443 either the cooling, heating, or dehumidifying mode is selected, butif heating operation is selected, determination is made in step 494whether the immediately previous operation was the refrigeration cycleindicated in FIG. 85. Moreover, for convenience the cycle indicated inFIG. 85 is termed No. 2 dehumidifying, defrosting operation, ordehumidifying C operation. Additionally, the refrigeration cycle stateindicated in FIG. 84 is termed No. 1 dehumidifying operation ordehumidifying H operation for convenience.

If it is determined in step 494 that the immediately previous operationwas dehumidifying C operation, dehumidifying H operation is performed instep 495 for a specified time (between about 30 seconds to 60 seconds).

Additionally, if frosting is detected during heating operation anddefrost switch is switched on (step 453), defrosting operation isperformed in the refrigeration cycle indicated in FIG. 85. That is tosay, in this case the cycle is defrosting C, and in order to be able torelease defrosting quickly the compressor 201 operates at high capacity,or in order to be able to maintain the heating function, passengercompartment inner air is caused to be recirculated in the duct 100, andfurthermore an auxiliary heater 700 not shown in FIGS. 82-89 is alsocaused to be operated. Accordingly, the amount of air of the blower 132is set to low and also the outside heat exchanger fan 251 is caused tostop. After the end of this defrosting is detected in step 497,dehumidifying H operation is caused to be performed once for a specifiedtime before moving to heating operation.

As a result of being able to perform the above-described dehumidifying Hoperation indicated in FIG. 84 and dehumidifying C operation as shown inFIG. 85, it is preferable to switch this dehumidifying H operation anddehumidifying C operation appropriately according to the refrigerationcycle state. Briefly, in a state wherein the refrigerant pressure ortemperature of the compressor discharge side is low, dehumidifying Hindicated in FIG. 85 is set, the outside heat exchanger 202 is employedas an evaporator, and absorption of heat is performed.

Conversely, in a state wherein high-pressure pressure is high, thedehumidifying C operation indicated in FIG. 85 is set, the outside heatexchanger 202 is caused to operate as a condenser, and heat radiation isperformed. Accordingly, moreover, an optimal state can be attained bycontrolling the capacity of the compressor 201 and the amount of air ofthe outside heat exchanger fan 251 on the basis of the low-pressure sidepressure of the refrigeration cycle.

FIG. 104 indicates this operation state typically. Ambient airtemperature is taken for the horizontal axis, and the vertical axisindicates, sequentially from the top, condensation temperature ofhigh-pressure side refrigerant (Tc), evaporation temperature oflow-pressure refrigerant (Te), amount of air of the outside heatexchanger blower 251, discharge capacity of the compressor 201, anddegree of opening of the air-mix damper 154. FIG. 87 indicates the timeof dehumidifying operation. A difference exists according to theinner/outer air mode, but in a case of the outer air mode, at an ambientair temperature of roughly -5° C. or less, effective dehumidificationcannot be performed and so heating operation is effected. Moreover, thisfreezing limit temperature comes to be a lower temperature during theinner air mode. Additionally, at an ambient air temperature of 20° C. ormore, normal cooling is performed and dehumidification of the air insidethe passenger compartment is achieved during cooling, and so specialdehumidification is not performed. Consequently, dehumidifying operationswitching of an ambient air temperature of roughly -5° C. to 20° C. isperformed. In a state of comparatively low ambient air temperature, thedehumidifying average operation indicated in FIG. 84 is set and heatabsorption from the outside heat exchanger 202 is performed. Conversely,in a state of comparatively high ambient air temperature, thedehumidifying C operation indicated in FIG. 85 is set, and heatradiation by means of the outside heat exchanger 202 is performed.Furthermore, foregoing dehumidifying operation the air-mix damper 154 isnormally set at MAX HOT and the total quantity of air is caused to flowto the heater 203 side, but when ambient air temperature is high andcooling-tinged operation is demanded, the air-mix damper 154 is set tocooling-side operation which causes the heater 203 to be bypassed.

The capacity of the compressor 201 is set to high capacity when ambientair temperature is particularly low and sufficient refrigerant flow forabsorbing heat from outside air is required, and in other states thecapacity of the compressor is reduced in accordance with load to achieveoperation that gives priority to saving energy. Additionally, theoutside heat exchanger blower 251, primarily during switching ofdehumidifying H operation and dehumidifying C operation, causes theamount of air to increase in accordance with a drop (rise) in ambientair temperature from that point. By means of this, the high-pressureside refrigerant temperature Tc is set to a substantially uniform value,and dehumidifying operation can be achieved.

FIG. 105 is a flowchart concretely representing the control modesconceptually indicated in FIG. 104. This flowcharts shown in FIG. 105indicates entirely the methods of dehumidification during dehumidifyingoperation. That is to say, control at the state wherein dehumidifyingoperation has been selected in step 443 is indicated.

First, in step 425 the difference between the target blowing temperatureTAO and the blowing temperature TA is seen. A state wherein thisdifference is 1° C. or more is a state wherein actual blowingtemperature is not high, and in this case basically the dehumidifying Hoperation indicated in FIG. 84 is set and heat absorption from theoutside heat exchanger 202 is performed. Conversely, when the differencebetween TAO and TA is -1° C. or less, it is a state wherein a sufficientamount of heating is attained by the condenser 203, and in this casebasically the dehumidifying C operation indicated in FIG. 85 is set andheat radiation at the outside heat exchanger 202 is performed.Accordingly, if the difference between TAO and TA is between -1° C. and1° C., and basically it is indicated that the operation state is nearthe target value in the auto mode or the limit value in the manual mode.

Next, refrigerant temperature Te at the low-pressure side in therespective modes is determined (step 426). If Te is 3° C. or more in astate wherein TAO - TA is 1° C. or more, the dehumidifying H mode is setin step 427 and, along with this, the outside heat exchanger blower 251stops and the capacity of the compressor 201 increases. That is to say,in this state the low-pressure side pressure of the compressor 201 is ata high state, and the low-pressure side pressure is cause to be loweredby increasing the capacity of the compressor.

In a case wherein Te is from 0° to 3° C. in step 426, basically thehigh-pressure pressure is high and the high-pressure side pressure is astate which is appropriate at the proximity of the freezing limit or inthe proximity of the freezing temperature, and so the dehumidifying Hmode is set and also the capacity of the compressor is set to risesomewhat.

In a state wherein it is determined in step 426 that Te is 0° C. orless, basically both high-pressure side pressure and the low-pressureside pressure exhibit a low state. In this case, the dehumidifying Hmode is set and, along with this, the amount of air of the outside heatexchanger blower 251 is increased and the amount of heat absorption isincreased. Accordingly, in step 430 it is determined whether the amountof air of the outside heat exchanger blower has risen to the maximumamount of air, if the maximum amount of air has not been reacheddehumidifying H operation is performed at that state, no further heatabsorption is performed when maximum heating has been reached, or ifthere is danger of the evaporator 207 freezing switching to the heatingoperation mode and not the dehumidifying H mode is performed.

Next, Te temperature determination by means of step 426 at a statewherein the difference between TAO and TA is determined to be between-1° C. and 1° C. in step 425 will be described. In this case, in a statewherein Te is determined to be 3° C. or more in step 426, thehigh-pressure side pressure state is the target value or the limitvalue, and also the low-pressure side pressure exhibits a high state. Inthis case heat absorption by means of the outside heat exchanger 202,and dehumidification is set to the dehumidifying C mode indicated inFIG. 85. However in this case as well it is not necessary to activelyperform heat radiation, and so the outside heat exchanger blower 251 isstopped.

When Te is determined to be between 0° and 3° C. in step 426, the stateis such that the high-pressure side refrigerant is at the refrigerant'starget value or limit value, and also that the low-pressure siderefrigerant is at the target value or within the appropriate range, andoptimal dehumidifying operation comes to be promoted. That is to say,the dehumidifying H mode is set and because heat absorption at theoutside heat exchanger 202 is not even necessary, the blower 251 iscaused to stop. Is a state wherein Te is determined to be 0° C. or lessin step 426, whereas the high-pressure side refrigerant is at the targetvalue or the limit value, the low-pressure side refrigerant exhibits alow-temperature (low-pressure) state. In this case the dehumidifying Hmode is set and, along with this, the amount of air of the outside heatexchanger blower 251 is increased and the amount of heat absorption iscaused to increase. Accordingly, it is determined in step 430 whetherthe amount of air of the outside heat exchanger blower 251 is atmaximum, and at a maximum state in dehumidifying operation there isdanger of the evaporator 207 freezing and so operation is switched toheating operation.

Next, Te temperature determination at a state wherein TAO - TA is -1° C.or less in step 425 will be described. In this case a Te of 3° C. ormore indicates a state wherein the high-pressure side refrigerant andthe low-pressure refrigerant are both high-temperature (high-pressure).Because sufficient heat absorption is being performed in this case,dehumidifying C is set and the outside heat exchanger 202 is employed asa heat radiator. Furthermore, the amount of air of the blower 251 israised to increase the amount of heat radiation. According it isdetermined in step 430 whether the amount of air of the outside heatexchanger blower 251 is at maximum, and at a maximum state first theair-mix damper 154 is caused to close gradually (step 437). Accordinglythe difference between TAO and TA is determined in this state and if itis still -1° C. of less, the capacity of the compressor 201 is presentlycaused to drop. This indicates that the blowing temperature is highereven in this state, and causes the quantity of heat at the heater 203 todecline by causing the capacity to drop.

In a state wherein Te is between 0° and 3° C. in step 426, although thehigh-pressure side refrigerant is high-pressure (high-temperature), thelow-pressure side refrigerant exhibits the freezing limit or optimaltemperature of the evaporator 207, and in this state dehumidifying Coperation is set and heat radiation is performed by the outside heatexchanger 202 and, along with this, the capacity of the compressor 201is caused to drop.

Additionally, a state wherein Te is 0° C. or less in step 426 indicatesthat although the high-pressure side refrigerant is high-pressure(high-temperature), the low-pressure side refrigerant is at alow-pressure (low-temperature) state, and in this state dehumidifying Coperation is set and heat radiation is performed by the outside heatexchanger 202 and, along with this, the capacity of the compressor 201is caused to drop in an attempt to raise the low-pressure side pressure.Additionally, the amount of air of the blower 251 is caused to drop.

A refrigeration cycle of an air-conditioning apparatus for automobileuse has heretofore been variously described, but an example of anexample layout of an automobile of the foregoing respective structureswill be described. In FIG. 106 a so-called one-box car is taken to be anelectric automobile, and an example of a layout of the respectivedevices in this one-box car is indicated. In the FIG. 800 is a battery,and in the present example sixteen 12 V batteries are taken to bemounted. 801 is a safety plug, and interrupts the high-voltage powersupply when inspecting or replacing the battery or the like.Furthermore, the high-voltage power supply is a voltage power supply of200 V, and a travel motor 803 and compressor 201 are driven by thishigh-voltage power supply 803 is a fuse which prevents excessive currentfrom flowing to the foregoing high-voltage power supply.

According to the present example an air-conditioning apparatus controlunit 300 and inverter of a compressor are both disposed within thepassenger compartment. This is done in order to provide protection fromthe penetration or rainwater and the like to maintain electricalinsulation.

In the FIG. 804 is a DC converter which supplies a specified voltage ofabout 12 V to an auxiliary battery 805 the voltage of which is caused tobe lower than the main battery 800. Also, in the FIG. 806 is a fillerwater plug cover, and replenishment of electrolyte to the battery 800 isperformed after detaching this cover. In the FIG. 807 is an inverter fordrive to the motor 800. Also, in the FIG. 708 is an ECU which controlsthis inverter to adjust the traveling state of the automobile. 809 is acontroller which controls a power steering motor 810. In the FIG. 811 isa vacuum pump, and vacuum created battery pump is maintained in areservoir tank and employed to drive the vehicle's brakes.

FIG. 107 is a conceptual diagram indicating the disposed state ofrespective devices for air-conditioning use in an automobile disposed inthis manner. The outside heat exchanger 202 is disposed substantiallyhorizontally below a driver seat. For this reason a shutter 255 notillustrated is employed as an air guide, and when the shutter 255 isopen wind is led to the outside heat exchanger 202 by means of a louverof the shutter. Additionally, a duct disposed with an evaporator,heater, and so on is disposed on the inner side of an instrument panelin front of a passenger seat. Furthermore, a unit for inner/outer airswitching damper 151 use and a unit for vent switching damper use arearranged to be adjacent to this duct 100. A unit housing a compressor201, accumulator 202, and four-way valve 213 is disposed below thepassenger compartment floor to a side of the outside heat exchanger 202.As described above, an inverter 852 and the control box 300 are disposedwithin the passenger compartment into which rainwater and the like donot penetrate. Additionally, a control panel 851 is disposed in alocation easily operated from the driver seat.

Moreover, according to the above-described example the compressor 201 isdriven by an electric motor and the discharge amount of the compressor201 is controlled by varying the speed of the motor, but it is alsoacceptable to use an article which does not vary discharge capacity asthe compressor 201. Along with this, it is also acceptable to make thedrive of the compressor 201 as well not exclusively an electric motorbut employ an engine or the like.

Additionally, according to the above-described example atemperature-operated type expansion valve or capillary tube is employedas an expansion means, but it is also acceptable to another electricaltype expansion valve which varies an amount of aperture in accordancewith an electrical signal.

Additionally, an air-conditioning apparatus according to the presentinvention is not exclusively for air conditioning of a passengercompartment of an electric automobile, but may be employed for airconditioning of a passenger compartment of an ordinary automobileemploying an internal combustion engine or for general air conditioningof other passenger vehicles. However, the present invention is moreeffective in a vehicle such as an electric automobile not having anauxiliary heat source.

EFFECTS OF THE INVENTION

As has been described above, the present invention disposes a heater andevaporator structuring a refrigeration cycle within a duct such that airis heated by means of heat radiation from the heater, and so temperaturecontrol for blown air can be performed over a wider range.

Additionally, because the present invention takes a heat exchangedisposed within a duct as a heater and an evaporator and specifies thefunctioning thereof, the respective heat exchangers can maintain thefunctioning thereof even during switching from cooling operation toheating operation, and sudden fogging of window glass and the like canbe prevented.

Additionally, one invention according to the present invention can varydischarge amount of a compressor by means of speed control of anelectric motor, and provides a bypass path to a side of a heater so asto perform control of air flow with an air-mix damper, and so by acombination of discharge capacity control of the compressor and speedcontrol of the air-mix damper, the temperature of blown air can becontrolled more exactly.

Furthermore, because one invention according to the present inventionemploys both an outside condenser for dedicated condenser use and anoutside evaporator for dedicated evaporator use as outside heatexchangers, the outside condenser and the outside evaporator canrespectively be disposed in optimal locations, and a high-efficiencyrefrigeration cycle can be performed.

Moreover, because one invention according to the present invention cancontinuously switch dehumidifying operation and heating operation inaccordance with application, prevention of fogging of window glassduring heating operation, prevention of freezing of an evaporator duringdehumidifying operation, and defrosting of an outside heat exchangerduring heating operation, can be favorably performed.

Additionally, one invention according to the present invention utilizesthree heat exchangers comprising an outside heat exchanger, condenser,and evaporator during dehumidifying operation, and heat-radiatingcapacity of the condenser can be controlled by means of varying theheat-exchanging capacity of the heat exchanger. By means of this,dehumidifying operation can be switched to heating-tingeddehumidification or normal dehumidification. Along with this,high-pressure protection of the effect during dehumidifying operationcan be favorably achieved.

Additionally, whereas one invention according to the present inventionemploys both an evaporator and an outside heat exchanger as heatabsorbers during dehumidifying operation and causes refrigerant to beevaporated, dehumidifying operation can be performed while favorablepreventing frosting on the evaporator, even in a state of low ambientair temperature, by disposing an evaporator pressure adjustment valve ona downstream side of the evaporator.

Additionally, in one invention according to the present invention abypass path is provided which causes refrigerant flow to bypass anevaporator and the opening and closing of this bypass path arecontrolled with an electromagnetic valve, and so the evaporationtemperature of refrigerant within the evaporator can be controlled bymeans of appropriately switching to a state of refrigerant flow to theevaporator or a state of refrigerant flow to the bypass path.

Furthermore, in one invention according to the present invention aheater disposed within a duct is divided into a condenser which performscondensation of refrigerant and an over-chiller which performsover-chilling of condensed liquid refrigerant, and so over-chilling canbe reliably provided even if the flow of air or temperature of airflowing into the heater fluctuates. Because of this, according to oneinvention according to the present invention, a refrigeration cycle canbe operated in a state constantly providing sufficient over-chilling,and operation of good efficiency can be achieved.

Moreover, according to one invention according to the present invention,a state wherein heat absorption is performed only by an outside heatexchanger during heating operation and a state wherein it is performedby both the outside heat exchanger and an evaporator are switched, andso heat is absorbed from the evaporator side as well at a time such asduring warmup when heating load is particularly large, and heating canbe achieved more rapidly. Furthermore, according to one inventionaccording to the present invention, because a cycle comprising acompressor, a heater, an outside heat exchanger, and an evaporator iscaused to be interposed when switching heating operation and defrostingoperation, liquid refrigerant condensed and collected by the outsideheat exchanger 202 is prevented from being sucked directly to thecompressor side. By means of this liquid compression of the compressorcan favorably be avoided.

Moreover, according to the present invention optimal dehumidification inaccordance with the refrigerant state can be achieved by employing aswitching means to switch between No. 1 dehumidifying operation using acompressor, a heater, a pressure-reducing means, an outside heatexchanger, and an evaporator and No. 2 dehumidifying and defrostingoperation using the condenser, the heater, the outside heat exchanger,the pressure-reducing means, and the evaporator. It is to be noted that,while, in the automotive air conditioners described above, thecompressor 201 is driven by means of an electric motor and thedischarging capacity of the compressor 201 is controlled by varying thespeed of rotation of the motor, the compressor 201 may otherwise beanother type which does not have a variable discharging capacity.Further, the compressor 201 need not necessarily be driven by anelectric motor but may be driven by an engine or the like.

Further, while, in the automotive air conditioners described above, atemperature differential expansion valve or a capillary tube is employedas expanding means, alternatively an electric expansion valve whichvaries a throttling amount in response to an electric signal may beemployed. Further, an automotive air conditioner according to thepresent invention may be used not only for air conditioning of a room ofan electric automobile but also for air conditioning of a room of anordinary automobile employing an internal combustion engine and anyother common vehicle. However, an automotive air conditioner accordingto the present invention is most effective for use with a vehicle whichdoes not have an auxiliary heat source such as an electric automobile.As described so far, according to the present invention, since a heaterand an evaporator which constitute a refrigerating cycle is disposed ina duct and air is heated by radiation of heat from the heater, thetemperature of air to be blown out can be controlled in wider range.Further, according to the present invention, since heat exchangersdisposed in a duct have individually specified functions as a heater andan evaporator, even upon changing over from cooling operation to heatingoperation, the heat exchangers can maintain the respective functionsthereof, and sudden fogging of the windshield and so forth can beprevented invention, since the discharging capacity of a compressor canbe varied by controlling rotation of an electric motor and a bypasspassageway is provided sidewardly of a heater such that the flow rate ofair may be controlled by means of an air mixing damper, the temperatureof air to be blown out can be controlled very finely by combination ofcontrol of the discharging amount of the compressor and control ofpivotal motion of the air mixing damper.

Further, according to the present invention, since the function of anoutside heat exchanger is changed over between a condenser function andan evaporator function in response to changing over between coolingoperation and heating operation, the refrigerating cycle can be operatedefficiently in any of cooling operation, heating operation anddehumidifying operation. Further, according to the present invention,since two outside heat exchangers are used including an outsidecondenser which serves only as a condenser and an outside evaporatorwhich serves only as an evaporator, the outside condenser and theoutside evaporator can be located at respective optimum positions, andthe refrigerating cycle can be achieved efficiently.

Further, according to the present invention, since the operation can bechanged over successively between dehumidifying operation and heatingoperation in accordance with an application, prevention of fogging ofthe windshield upon heating operation, prevention of freezing of anevaporator upon dehumidifying operation and defrosting of an outsideheat exchanger upon heating operation can be performed well. Further,according to the present invention, making use of the fact that threeheat exchangers are used upon dehumidifying operation including anoutside heat exchanger, a condenser and an evaporator, the heatradiating capacity of the condenser can be controlled by varying theheat exchanging capacity of the outside heat exchanger. Consequently,dehumidification can be changed over between ordinary dehumidificationand dehumidification having some heating effect. In addition, protectionof the refrigerating cycle against a high pressure upon dehumidifyingoperation can be achieved well.

Further, according to the present invention, while both of an evaporatorand an outside heat exchanger are used as heat sinks to evaporaterefrigerant upon dehumidifying operation, since an evaporating pressureregulating valve is disposed on the downstream side of the evaporator,even when the temperature of outside air is low, dehumidifying operationcan be performed while preventing frosting of the evaporator well.

Further, according to the present invention, since a bypass passagewayfor flowing refrigerant bypassing an evaporator is provided andopening/closing movement of the bypass passageway is controlled by meansof a solenoid valve, the evaporating temperature of refrigerant in theevaporator can be controlled by suitably changing over between acondition wherein refrigerant flows into the evaporator and anothercondition wherein refrigerant flows into the bypass passageway. Further,according to the present invention, since a heater disposed in a duct isdivided into a condenser for condensing refrigerant and a subcooler forsubcooling condensed liquid refrigerant, refrigerant can have asubcooling degree with certainty even if the flow rate or thetemperature of air to be admitted into the heater varies. Consequently,according to the present invention, the refrigerating cycle can alwaysbe operated while refrigerant has a sufficient subcooling degree, andefficient operation can be achieved.

Further, according to the present invention, since the heat absorbingcondition upon heating operation is changed over between a conditionwherein heat is absorbed only by means of an outside heat exchanger andanother condition wherein heat is absorbed by means of both of theoutside heat exchanger and an evaporator, when the heating load isparticularly high such as upon warming up, heat is absorbed also fromthe evaporator side and heating can be achieved quickly.

The other embodiment of the present invention is described hereinafter.

Referring first to FIG. 86, there is shown an automotive air conditionerin which a refrigerating cycle according to the present invention isincorporated. The automotive air conditioner shown is carried on anelectric automobile and includes a duct 1001 for introducing draft airinto the room of the automobile, a fan 1002 disposed in the duct 1001for producing an air flow to be introduced into the room of theautomobile, and a refrigerating cycle 1003 of the accumulator type.

The duct 1001 has, at an upstream end thereof, an internal air inletport 1004 for taking air in the automobile room (internal air) into theduct 1001 and an external air inlet port 1005 for taking air outside theautomobile room (external air) into the duct 1001. The amounts of air tobe taken in through the inlet ports 1004 and 1005 are adjusted by adamper 1006. A downstream end of the duct 1001 communicates with a DEFoutlet port 1007 for discharging draft air therethrough toward a windowglass of the automobile, a VENT outlet port 1008 for discharging draftair therethrough toward the upper half of the body of the driver, and aFOOT outlet port 1008 for discharging draft air therethrough toward thefeet of the driver or around them. The outlet ports 1007 to 1009 areopened or closed by outlet port switching dampers 1010, 1011 and 1012,respectively, which operate in accordance with a selected outlet portmode.

An interior evaporator 1013 and an interior condenser 1014 of therefrigerating cycle 1003 are disposed in the duct 1001, and an airmixing damper 1015 for adjusting the amount of draft air to beintroduced into the interior condenser 1014 is provided in the duct1001. The air mixing damper 1015 adjusts the ratio between the amount ofair to pass through the interior condenser 1014 and the amount of air topass through a bypass passageway 1016 (passageway which bypasses theinterior condenser 1014) formed in the duct 1001 to effect adjustment ofthe temperature of air to be blown out.

The refrigerating cycle 1003 includes a four-way valve 1017 which canchange over the circulating direction of refrigerant, and accordingly,it can a perform heating operation and a cooling operation based on thechange-over of the four-way valve 1017.

The refrigerating cycle 1003 includes, in addition to the interiorevaporator 1013 and the interior condenser 1014 mentioned above, arefrigerant compressor 1019 which is driven to rotate by an electricmotor 1018, an exterior heat exchanger 1021 which receives draft wind ofan electric fan 1020 and functions as an evaporator upon heatingoperation buts functions as a condenser upon cooling operation, asubcooling control valve 1022 for controlling the subcooling degreeobtained by the interior condenser 1014, an evaporation pressureregulating valve 1023 interposed between the interior evaporator 1013and the exterior heat exchanger 1021, and an accumulator 1024 disposedon the upstream side of the refrigerant compressor 1019. Thosefunctioning parts are connected to each other by a refrigerant pipe1025.

Further, the refrigerating cycle 1003 has a bypass passageway 1026 forcommunicating the subcooling control valve 1022 and the exterior heatexchanger 1021 with each other bypassing the exterior evaporator 1013and the evaporation pressure regulating valve 1023. Upon heatingoperation, refrigerant flows along the bypass passageway 1026 so thatdehumidifying heating is not performed but heating based on an externalair mode (in which external air is introduced in) can be performed. Asolenoid valve 1027 for opening or closing the bypass passageway 1026 isprovided for the bypass passageway 1026. The solenoid valve 1027 iscontrolled so that the bypass passageway 1026 may be closed when acooling operation or a dehumidifying heating operation is performed.Further, a plurality of check valves 1028 to 1031 for preventing a backflow of refrigerant upon cooling operation or upon heating operation areprovided suitably for the refrigerant pipe 1025.

The interior condenser 1014 has a heat exchanging section where heat isexchanged between refrigerant and draft air, and the heat exchangingsection has a three-layer structure wherein it is divided into threestream area portions including an upper stream area portion 1014a, amiddle stream area portion 1014b and a lower stream area portion 1014cand the upper stream area portion 1014a is disposed on the lee side ofthe middle stream area portion 1014b in the duct 1001 while the lowerstream area portion 1014c is disposed on the windward side of the middlestream area portion 1014b in the duct 1001 so that the stream areaportions 1014a, 1014b and 1014c may provide opposing flows to draft airflowing in the duct 1001.

The subcooling control valve 1022 is shown in more detail in FIG. 87.Referring to FIG. 87, the subcooling control valve 1022 includes a valvebody 1022b in which a throttle section 1022a is formed, a diaphragm1022c provided at the top of the valve body 1022b, a valve member 1022dfor opening or closing the throttle section 1022 upon displacement ofthe diaphragm 1022c, a regulating spring 1022g for normally biasing thevalve member 1022d by way of a pin 1022e and a spring guide 1022f sothat the opening of the throttle section 1022a may be increased (in theupward direction in FIG. 87), a temperature sensitive tube 1022h fortransmitting a variation of the internal pressure of the valve body1022b to the upper side of the diaphragm 1022c, and a mantle pipe 1022ifor transmitting a high pressure on the upstream side of the throttlesection 1022a to the lower side of the diaphragm 1022c.

An entrance port 1022j and an exit port 1022k are attached to the valvebody 1022b, and the entrance port 1022j is communicated with the exit ofthe interior condenser 1014 while the exit port 1022k is communicatedwith the entrance of the interior evaporator 1013 and the entrance ofthe bypass passageway 1026. The entrance and exit ports 1022j and 1022kare communicated with each other by way of the throttle section 1022a.

The temperature sensitive tube 1022h has gas refrigerant enclosed in theinside thereof and is provided in contact with a refrigerant passageway1014d which interconnects the middle stream area portion 1014b and thelower stream area portion 1014d of the interior condenser 1014. Thetemperature sensitive tube 1022h thus converts a variation oftemperature of the refrigerant flowing through the refrigerantpassageway 1014d into a variation of pressure and transmits the pressurevariation to the upper side of the diaphragm 1022c byway of a capillarytube 1221.

The mantle tube 1022i extracts a high pressure on the upstream of thelower stream area portion 1014c, that is, at the refrigerant passageway1014d, and transmits the high pressure to the lower side of thediaphragm 1022c in order to prevent an influence of a pressure losswhich may be caused by the flow resistance of the lower stream areaportion 1014c of the interior condenser 1014.

The valve member 1022d is held on a stopper 1022n which fits with thetop of the valve body 1022b with an O-snap ring 1022m interposedtherebetween, and opens or closes the throttle section 1022a when thestopper 1022n is slidably moved (in the upward or downward direction inFIG. 87) on the valve body 1022b by displacement of the diaphragm 1022c.The valve member 1022d is moved to a position at which the pressure inthe temperature sensitive tube 1022h acting upon the upper side of thediaphragm 1022c and the high pressure and the biasing force of theregulating spring 1022g which both act upon the lower side of thediaphragm 1022c are balanced with each other, and the opening of thethrottle section 1022a depends upon the displacement of the valve member1022d.

The regulating spring 1022g is provided so that the biasing forcethereof may be adjusted by means of an adjusting screw 1220. Theadjusting screw 1220 is screwed in a hitching 1022q mounted at thebottom end of the valve body 1022b with an o-snap ring 22p interposedtherebetween.

The subcooling control valve 1022 is constructed such that a lowpressure on the downstream side of the throttle section 1022a isprevented from being transmitted to the lower side of the diaphragm1022c by the O-snap ring 1022m while a high pressure is transmitted tothe lower side of the diaphragm 1022c only by way of the mantle pipe1022i. Meanwhile, a communicating hole 1022 is formed in the springguide 1022f and communicates a spring accommodating chamber 1022r foraccommodating the regulating spring 1022g therein and the upstream sideof the throttle section 1022a with each other. Thus, the high pressureon the upstream side of the throttle section 1022a is introduced intothe spring accommodating chamber 1022r through the communicating hole1022s so that the influence of the high pressure applied to the springguide 1022f is cancelled.

In the subcooling control valve 1022 having the construction describedabove, the biasing force of the regulating spring 1022g is set so thatthe subcooling degree between the middle stream area portion 1014b andthe lower stream area portion 1014c of the interior condenser 1014 withwhich the temperature sensitive tube 1022h contacts may be apredetermined value (2° to 10° C.).

Operation of the automotive air conditioner will be describedsubsequently with reference to the Mollier diagrams shown in FIGS. 88 to91. It is to be noted that any point on any of the Mollier diagramsshown in FIGS. 88 to 91 indicates a state point of the refrigerant onthe refrigerating cycle shown in FIG. 86. (a) In Heating Operation

The passageway of the four-way valve 1017 is changed over to theposition indicated by solid lines in FIG. 86, and the air mixing damper1015 closes (the position indicated by solid lines in FIG. 86) thebypass passageway 1016 which bypasses the interior condenser 1014 sothat all draft air may pass the interior condenser 1014.

High temperature, high pressure gas refrigerant (point A in FIG. 88)compressed by the refrigerant compressor 1019 is introduced into theinterior condenser 1014 as indicated by solid line arrow marks in FIG.86 through the four-way valve 1017 and the check valve 1029. In theinterior condenser 1014, the gas refrigerant having a subcooling degreeis first cooled in the upper stream area portion 1014a and thencondensed into liquid in the middle stream area portion 1014b so that,at the exit of the middle stream area portion 1014b with which thetemperature sensitive tube 1022h contacts, the subcooling degree of apredetermined value (point B in FIG. 88) is obtained by control of thesubcooling control valve 1022.

The liquid refrigerant having such subcooling degree is further cooled,as dehumidifying heating operation based on the internal air mode (inwhich internal air is introduced in) is performed, by cooling windcooled by the interior evaporator 1013 when it passes the lower streamarea portion 1014c of the interior condenser 1014. Consequently, at theexit of the interior condenser 1014, a maximum subcooling degree (pointC in FIG. 88) which can possibly be obtained at the lower stream areaportion 1014c in accordance with a temperature difference between thetemperature of the cool wind and the saturation temperature of therefrigerant on the upstream of the lower stream area portion 1016c canbe obtained.

The liquid refrigerant flowing out from the interior condenser 1014 isdecompressed (point D in FIG. 88) at the subcooling control valve 1022,and then exchanges, when it passes the interior evaporator 1013, heat(point. E in FIG. 88) with the draft air flowing in the duct 1001,whereafter it is decompressed (point F in FIG. 88) at the evaporationpressure regulating valve 1023 and then exchanges, when it passes theexterior heat exchanger 1021, heat (point G in FIG. 88) with draft airblown by the electric fan 1020. The refrigerant evaporated in theexterior heat exchanger 1021 is introduced through the four-way valve1017 into the accumulator 1024, from which only gas refrigerant issucked into the refrigerant condenser 1019.

Meanwhile, internal air introduced into the duct 1001 by operation ofthe fan 1002 is dehumidified when it passes the exterior evaporator1013, and then is overheated when it passes the interior condenser 1014,whereafter it is blown out into the automobile room from a selected oneor ones of the outlet ports 1007 to 1009.

When dehumidification is not performed during such heating operation,the solenoid valve 1027 is opened. Consequently, the refrigerant (pointF in FIG. 89) decompressed at the subcooling control valve 1022 isintroduced into the exterior heat exchanger 1021 by way of the bypasspassageway 1026 without passing the interior evaporator 1013 and theevaporation pressure regulating valve 1023 and then evaporated in theexternal heat exchanger 1021, whereafter it is sucked (point G in FIG.89) into the refrigerant compressor 1019 past the accumulator 1024.

In such heating operation in the external air mode, liquid refrigeranthaving a subcooling degree of a predetermined value (point B in FIG. 89)at the exit of the middle stream area portion 1014b of the interiorcondenser 1014 is cooled, when it subsequently passes the lower streamarea portion 1014c, by draft wind of external air introduced into theduct 1001. Accordingly, the refrigerant flowing in the lower stream areaportion 1014c can ideally obtain a subcooling degree (point C in FIG.89) of a temperature difference between the temperature of draft air(external air temperature) and the saturation temperature of therefrigerant on the upstream of the lower stream area portion 1014c. (b)In Cooling Operation

The passageway of the four-way valve 1017 is changed over to theposition indicated by broken lines in FIG. 86 while the solenoid valve1027 provided in the bypass passageway 1026 is closed.

High temperature, high pressure gas refrigerant (point A in FIG. 90)compressed by the refrigerant compressor 1019 is introduced, after itpasses the four-way valve 1017, into the external heat exchanger 1021 asindicated by broken line arrow marks in FIG. 86 and then condensed inthe external heat exchanger 1021 by draft air blown from the electricfan 1020. Then, the refrigerant is introduced into the interiorcondenser 1014 through the check valve 1031 and then exchanges heat withdraft air in the interior condenser 1014 so that it is condensed intoliquid. In the interior condenser 1014, a subcooling degree of apredetermined value (point B in FIG. 90) is obtained at the exit of themiddle stream area portion 1014b by the subcooling control valve 1022,similarly as upon heating operation.

Here, when a maximum cooling degree (MAX COOL) is set by the operator,the air mixing damper 1015 fully closes (position indicated by chainlines in FIG. 86) the interior condenser 1014. Consequently, cool windcooled by the interior evaporator 1013 is not blown to the interiorcondenser 1014, and accordingly, the lower stream area portion 1014c ofthe interior condenser 1014 serves as a mere passage for refrigerant.

Accordingly, the liquid refrigerant having a subcooling degree of thepredetermined value is not cooled any more when it passes the lowerstream area portion 1014c of the interior condenser 1014, andconsequently, it flows out from the interior condenser 1014 while itkeeps the subcooling degree of the predetermined value.

Thereafter, the refrigerant decompressed (point F in FIG. 90) at thesubcooling control valve 1022 is evaporated by heat exchange thereofwith draft air in the interior evaporator 1013, and then, after itpasses the check valve 1028 and the four-way valve 1017, it is sucked(point G in FIG. 90) into the refrigerant compressor 1019 past theaccumulator 1024.

Meanwhile, the draft air (internal air) introduced into the duct 1001 byoperation of the fan 1002 is cooled when it passes the interiorevaporator 1013, and then passes the bypass passageway 1016 withoutpassing the interior condenser 14, whereafter it is blown out into theautomobile room from a selected one or ones of the outlet ports 1007 to1009.

When, in such cooling operation, part of cool wind cooled in theinterior evaporator 1013 is allowed to pass the interior condenser 1014in accordance with the opening of the air mixing damper 1015 so as toeffect adjustment of the temperature, liquid refrigerant having asubcooling degree of the predetermined value (point B in FIG. 91) isfurther cooled by the cool air flowing to the interior condenser 1014side when it passes the lower stream area portion 14c of the interiorcondenser 1014. Accordingly, the refrigerant flowing out from theinterior condenser 1014 can ideally obtain a subcooling degree (point Cof FIG. 91) of a value equal to a temperature difference between thetemperature of the cool wind and the saturation temperature of therefrigerant on the upstream of the lower stream area portion 1014c.

As described above, in the present embodiment, the opening of thethrottle portion 1022a of the subcooling control valve 1022 is adjustedso that a subcooling degree of the predetermined value may be obtainedat the exit of the middle stream area portion 1014b of the interiorcondenser 1014 with which the temperature sensitive tube 22h contacts.Consequently, at the lower stream area portion 1014 of the interiorcondenser 1014, a maximum possible subcooling degree which can beobtained at the lower stream area portion 1014c in accordance with thetemperature of draft air blown to the lower stream area portion 1014ccan be obtained.

It is to be noted that, while the interior condenser 1014 in the presentembodiment has a three-layer structure, alternatively a two-layerstructure including the lower stream area portion 1014c and the upperand middle area portion with respect to the location where thetemperature sensitive tube 1022h contacts may be employed. Further, nolayer structure may necessarily be employed, and the upper stream areaportion 1014a, the middle stream area portion 1014b and the lower streamarea portion 1014c in the embodiment described above may be formed on asame plane.

Further, while the subcooling control valve 1022 includes the mantlepipe 1022i in order to prevent a possible influence of a pressure lossin the interior condenser 1014, the mantle pipe 1022i need not beemployed where the influence of a pressure loss at the lower stream areaportion 1014c need not be taken into consideration.

While the air is employed as the cooling medium which exchanges heatwith refrigerant flowing in the interior condenser 1014, such liquid aswater or oil may be employed instead.

Referring now to FIG. 92, there is shown another air conditioner for anelectric automobile. The air conditioner can perform a dehumidifyingheating operation and includes an interior evaporator 1033, a subcoolingheat exchanger 1032 and a main condenser 1033 all disposed in this orderfrom the upstream side in a duct 1001. An exterior evaporator 1034 forreceiving draft air from an electric fan 1030 to evaporate refrigerantis provided outside the duct 1001.

A subcooling control valve 1022 includes a temperature sensitive tube1022h held in contact with a refrigerant passageway 1014dinterconnecting the subcooling heat exchanger 1032 and the maincondenser 1033 and is set so that a subcooling degree of a predeterminedvalue may be obtained at the exit of the main condenser 1033.

In the present embodiment, the subcooling heat exchanger 1032 and themain condenser 1033 cooperatively constitute a refrigerant condenser,and the subcooling heat exchanger 1032 acts as a lower stream areaportion.

When a dehumidifying heating operation is to be performed, liquidrefrigerant having a subcooling degree of a predetermined value at theexit of the main condenser 1033 is further cooled, when it passes thesubcooling heat exchanger 1032, by cool wind cooled in the interiorevaporator 1013 so that it can obtain a maximum possible subcoolingdegree which can be obtained at the subcooling heat exchanger 1032.

On the other hand, when a dehumidifying heating operation is notperformed, the liquid refrigerant having a subcooling degree of thepredetermined value receives, when it passes the subcooling heatexchanger 1032, draft wind of external air introduced into the duct 1001based on the external air mode so that it can obtain a subcooling degreecorresponding to the temperature of the external air.

Referring now to FIG. 93, there is shown a further air conditioner foran electric automobile. The air conditioner in the present embodimentcan perform a cooling operation and includes an interior evaporator 1013provided in a duct 1001, and an interior head exchanger 1035 provided onthe lee side of the interior evaporator 1013 in the duct 1001. Theamount of draft air to the interior heat exchanger 1035 is adjusted inaccordance with the opening of an air mixing damper 1015. An externalcondenser 1036 is provided on the outside the duct 1001 and receivesdraft wind from an electric fan 1020 to condense high temperature, highpressure gas refrigerant compressed by a refrigerant compressor 1019.

A subcooling control valve 1022 includes a temperature sensitive tube1022h held in contact with a refrigerant passageway 1014dinterconnecting the interior heat exchanger 1035 and the exteriorcondenser 1036 and is set so that a subcooling degree of a predeterminedvalue may be obtained at the exit of the exterior condenser 1036.

In the present embodiment, the interior heat exchanger 1035 and theexternal condenser 1036 constitute a refrigerant condenser while theinterior heat exchanger 1035 serves as a lower stream area portion, andthe external condenser 1036 is disposed outside the duct 1001.

Now, when a maximum cooling degree (MAX COOL) is set by the operator,the air mixing damper 1015 fully closes (position indicated by chainlines in FIG. 93) the interior heat exchanger 1035, and consequently,the interior heat exchanger 1035 serves as a mere passage forrefrigerant. Accordingly, liquid refrigerant condensed by the exteriorcondenser 1036 is not cooled any more when it passes the interior heatexchanger 1035, but flows out from the interior heat exchanger 1035while it keeps the subcooling degree of the predetermined value.

When part of cool wind cooled in the interior evaporator 1013 is allowedto pass the interior heat exchanger 1035 in accordance with the openingof the air mixing damper 1015 so as to effect adjustment of thetemperature, liquid refrigerant having a subcooling degree of thepredetermined value is further cooled by the cool air flowing to theinterior heat exchanger 1035 side when it passes the interior heatexchanger 1035, and consequently, a subcooling degree corresponding tothe temperature of the cool wind can be obtained.

Referring now to FIG. 94, there is shown a front elevational view of arefrigerant condenser of a refrigerating cycle according to a fourthpreferred embodiment of the present invention. The refrigerant condenser1014 is constructed as a heat exchanger of the layer type which includesa heat exchanging section including a large number of (1006 in thepresent embodiment) tubes 1037 serving as refrigerant passageways and alarge number of heat radiating fins 1038 layered alternately with thetubes 1037, and a pair of headers 1039 and 1040 disposed on the oppositeends of the tubes 1037.

The tubes 1037 are extrusion molded articles of aluminum and each formedin a flattened profile.

The fins 1038 are roller-shaped articles of a thin aluminum plate shapedinto a corrugated profile and each has a large number of louvers .(notshown) formed on a surface thereof.

The headers 1039 and 1040 have a circular cross section and each has oneor a plurality of partition plates 1041 provided in the inside thereof.The partition plates 41 partition the inside of each of the headers 1039and 1040 in the longitudinal direction so that refrigerant flowing inthe heat exchanging section may be turned back. The partition plates1041 are provided, in the header 1039, between the second and thirdtubes 1037 from above in FIG. 94, between the fourth and fifth tubes1037 and between the fifth and sixth tubes 1037, and, in the otherheader 1040, between the fourth and fifth tubes 1037 from above in FIG.94.

Here, when portions of the header 1039 partitioned by the threepartition plates 1041 are called, in order from above in FIG. 94, firstheader portion 1039a, second header portion 1039b, third header portion1039c and fourth header portion 1039d, an entrance pipe 1042 and an exitpipe 1043 for refrigerant are connected to the first header portion1039a and the fourth header portion 1039d, respectively, and theopposite ends of a mounting pipe 1044 (which will be hereinafterdescribed) having a channel-shaped profile as--viewed from the front areconnected to the second and third header portions 1039b and 1039c.

The headers 1039 and 1040 have elongated holes 1045 formed therein inwhich the opposite end portions of the tubes 1037 are inserted, andfurther have three and one insertion holes 1046 (refer to FIG. 95)formed in the side walls opposite to the elongated holes 1045 thereof,respectively. The partition plates 1041 are individually inserted in theinsertion holes 1046 of the headers 1039 and 1040. The header 1039further has a pair of connecting holes (not shown) formed therein towhich the input pipe 1042 and the exit pipe 1043 are connected, and hasanother pair of connecting holes 1047 (refer to FIG. 95) formed thereinto which the mounting pipe 1044 are connected.

A method of assembling the refrigerant condenser 1014 will be describedsubsequently with reference to FIG. 95 in which the header 1039 isshown.

First, the tubes 1037 and the fins 1038 are layered alternately to formthe heat exchanging section, and then the opposite end portions of thetubes 1037 are inserted into the elongated holes 1045 of the headers1039 and 1040 to assemble the headers 1039 and 1040 thereby to fix thetubes 1037, the fins 1038 and the headers 1039 and 1040.

Then, one of the partition plates 1041 is assembled to the header 1040,and the other partition plates 1041, the entrance pipe 1042, the exitpipe 1043 and the mounting pipe 1044 are assembled to the other header1039, whereafter portions of the components to be brazed are joined byintegral brazing, thereby completing the assembly of the refrigerantcondenser 1014.

The mounting pipe 1044 described above is provided for mounting thetemperature sensitive tube 1022h of the subcooling control valve 1022thereon. The mounting pipe 1044 is formed so as to have, at a portionthereof for contacting with the temperature sensitive tube 1022h, aconcave recessed face as shown in FIG. 96 in order to assure a largecontact area with the temperature sensitive tube 1022h. Further, wherethe contact portion of the mounting pipe 1044 with the temperaturesensitive tube 1022h is recessed, the mounting height H of the mountingpipe 1044 and the temperature sensitive tube 1022h can be reducedcomparing with that of an alternative arrangement wherein thetemperature sensitive tube 1022h is mounted on an alternative mountingpipe 1044a having a circuit cross section as shown in FIG. 97.Consequently, the mounting space of the temperature sensitive tube 1044can be reduced. It is to be noted that, in order to prevent the duct1001 from being increased in size by an arrangement of the mounting pipe1044 in the duct 1001, in the present embodiment, the mounting pipe 1044is provided such that it extends outwardly of the duct 1001.

Since the refrigerant condenser 1014 in the present embodiment iscontrolled by the subcooling control valve 1022 so that the subcoolingdegree may have a predetermined value in the mounting pipe 1044 on whichthe temperature sensitive tube 1022h is mounted, on the downstream side(in the lower stream area portion) of the mounting pipe 1044, asubcooling degree of up to a temperature difference between thetemperature of draft air blown to the refrigerant condenser 1014 and thesaturation temperature of refrigerant flowing in the mounting pipe 1044can be obtained. In short, since a temperature variation of draft air isabsorbed on the downstream side of the mounting pipe 1044, asubstantially uniform temperature distribution in a two gas-liquid phasecondition can be obtained on the upstream side of the mounting pipe1044.

Consequently, when the refrigerant condenser 1014 is to be used as aheating heat exchanger of a heat pump cycle, since the temperaturedistribution of the heat exchanging section in the leftward andrightward directions of the refrigerant condenser 1014 (leftward andrightward directions in FIG. 94) can be maintained substantiallyuniform, the temperature distribution of draft air to be blown into theautomobile room can be kept uniform between the driver's seat side andthe passenger's seat side.

It is to be noted that, while, in the present embodiment, the headers1039 and 1040 have a circular cross section, such a header 1048 of thesplit type which is constituted from a plate header 1048a and a tankheader 1048b as shown in FIG. 98 may be employed instead. In thisinstance, each partition plate 1041 is assembled not by a method whereinit is inserted into the header 1039 or 1040 from the outside but byanother method wherein it is held between the plate header 1048a and thetank head 1048b.

Further, while the refrigerant condenser 1014 in the present embodimentis formed as a heat exchanger of the layer type, such a heat exchangerof the serpentine type as shown in FIG. 1014 may be employed instead. Inthis instance, the mounting pipe 1044 can be formed by partiallyextending a tube 1037, which is curved in a serpentine-like shape, suchthat it projects outwardly from a bracket 1049 for mounting therefrigerant condenser 1014 on the automobile.

Having now fully described the invention, it will be apparent to one ofordinary skill in the art that many changes and modifications can bemade thereto without departing from the spirit and scope of theinvention as set forth herein.

What is claimed is:
 1. An automotive air conditioner, comprising:a ductdefining a passageway for air to a room of an automobile; a blower forblasting air into the room of the automobile by way of said duct; anevaporator disposed in the inside of said duct for causing refrigerantto exchange heat with air to be sent into the room of the automobile; aheater disposed on the downstream of said upstream side heat exchangerin said duct for causing refrigerant to exchange heat with air to besent into the room of the automobile; an outside heat exchanger disposedoutside said duct for causing air outside the room and refrigerant toexchange heat with each other; heat being taken from air in saidevaporator to evaporate refrigerant while heat is exchanged betweenrefrigerant of a high temperature and air in said heater so thatdehumidifying operation wherein heating of air is performed; flowpassage changing over means for changing over the condition of saidoutside heat exchanger upon dehumidifying operation from a conditionwherein said outside heat exchanger is not used as a heat exchangerbetween refrigerant and air or said outside heat exchanger is used as arefrigerant condenser to another condition wherein said outside heatexchanger is used as a refrigerant evaporator; a frosting sensor fordetecting a frosted condition of said evaporator; and controlling meansfor controlling, when a frosted condition of said evaporator is forecastor detected by said frosting sensor upon dehumidifying operation, saidflow passage changing over means to change over the condition of saidoutside heat exchanger upon dehumidifying operation from the conditionwherein said outside heat exchanger is not used as a heat exchangerbetween refrigerant and air or said outside heat exchanger is used as arefrigerant condenser to the condition wherein said outside heatexchanger is used as a refrigerant evaporator.
 2. An automotive airconditioner, comprising:a duct defining a passageway for air to a roomof an automobile; a blower for blasting air into the room of theautomobile by way of said duct; an evaporator disposed in the inside ofsaid duct for cooling the air by evaporating refrigerant; a heaterdisposed on the downstream of said evaporator; an outside heat exchangerdisposed outside said duct for causing air outside the room andrefrigerant to exchange heat with each other; an expanding means forexpanding and decompressing refrigerant; a changing over means forswitching refrigerant flow to said evaporator, said heater and saidoutside heat exchanger, said changing over means switching at leastamong a heating operation wherein refrigerant circulates in the order ofsaid compressor, said heater, said expanding means and said outside heatexchanger, a first dehumidifying operation wherein refrigerantcirculates in the order of said compressor, said heater, said expandingmeans, said outside heat exchanger and said evaporator, a seconddehumidifying operation and defrosting operations wherein refrigerantcirculates said compressor, said heater, said outside heat exchanger,said expanding means and said evaporator; a control means forcontrolling said change over means in such a manner that when one ofsaid second dehumidifying operation and defrosting operation changesinto said heating operation, said first dehumidifying operation isperformed for a predetermined time before changing and then said heatingoperation is performed.
 3. An automotive air conditioner according toclaim 2, wherein said compressor varies its discharge capacity based ona signal generated from said control means, said outside heat exchangerhas a blower which forcedly blows air thereto and is controlled by saidcontrol means, said control means changes between said firstdehumidifying operation and said second dehumidifying operation andcontrols air amount generated by said blower for said outside heatexchanger in response to one of refrigerant pressure and temperature ata suction side or a discharge side of said compressor.
 4. An automotiveair conditioner according to claim 3, wherein when said control meansperforms dehumidifying operation under the condition such that one ofrefrigerant pressure and temperature at discharge side of saidcompressor is high and one of refrigerant pressure and temperature atsuction side of said compressor is also high, said control means selectssaid second dehumidifying operation and increases air amount generatedby said blower for said outside heat exchanger, and performs when saidcontrol means performs dehumidifying operation under the condition suchthat one of refrigerant pressure and temperature at discharge side ofsaid compressor is low and one of refrigerant pressure and temperatureat suction side of said compressor is also low, said control meansselects said first dehumidifying operation and increases air amountgenerated by said blower for said outside heat exchanger.
 5. Anautomotive air conditioner according to claim 4, wherein when saidcontrol means performs dehumidifying operation under the condition suchthat one of refrigerant pressure and temperature at discharge side ofsaid compressor is high and one of refrigerant pressure and temperatureat suction side of said compressor is low, said control means selectssaid second dehumidifying operation, decreases the capacity of saidcompressor and decreases air amount generated by said blower for saidoutside heat exchanger, and when said control means performsdehumidifying operation under the condition such that one of refrigerantpressure and temperature at discharge side of said compressor is low andone of refrigerant pressure and temperature at suction side of saidcompressor is high, said control means selects said first dehumidifyingoperation, increases the capacity of said compressor and decreases airamount generated by said blower for said outside heat exchanger.